So I'm looking to replace my Leupold 1.5-4x20 for a setup more suited to my main useage - home defense.

My problem is, there's too many good products on the market. I've managed to narrow it down to a few, but still can't quite decide which one to go with. Ordered roughly by price.

1) Aimpoint PRO
Pros:
Fits very well with the block 1 inspired styling of my rifle
Cheapest option
It's an Aimpoint
Military usage for known durability
Cons:
Not a huge fan of the view through it (or other tube sights)

2) Trijicon MRO
Pros:
Weight
Size
Not crazy pricing
Fanboy levels of love for it, but for once, not entirely without reason
Cons:
IMO, this may be the ugliest sight ever put on an AR15, and despite function > form, I'm having a hard time moving past that.
I'm really struggling to actually like this thing.

3) Meprolight M21
Pros:
Military usage for known durability
No battery life is better than long battery life
Light collectors on top, sides, and front
Triangle reticle
Cons:
Haven't seen or handled one in person
Not a whole lot of users over here, so not a whole ton of data on them
Can't find data on visibility indoors in low light or with only a WML
No batteries can lead to washout and some other issues.

4) Trijicon RX06
Pros:
Looks are right on par with the PRO
No batteries.
Size
Weight
Triangle reticle
Cons:
Same cons as M21
Only has light collector on front
Will likely need a polarizing filter which bumps price up

5) Trijicon RX34
Pros:
Huge FOV
No batteries
Cons:
Same cons as M21
Size = awkward looking proportions
Only has light collectors on top and sides
Large dot
Expensive

I'm currently leaning towards the RX06, but I'm a bit concerned about how it'll do with only a front collector. From those of y'all with experience with these sights, or just more knowledge and experience in general than I, which do y'all recommend?

Home defense use?

Aimpoint.

You can find a Comp M2 for $200-300 in the EE. I saw an M3 in the EE last week for around $275 IIRC.

I never had a problem with the "tube" style red dots. Training will fix that though.

Look at the Meprolight tru dot too. It's AA powered, has a huge field of view (Eotech style reflex), and has motion activation. I had a lithium energizer AA in the one I had for 2 or 3 months and it always turned on when I grabbed the rifle. 

Of the ones you mentioned I would prefer the PRO but I'm an AP guy. From what I've read the tritium and fiber optic sights will without a doubt washout with flashlight usage. The MEPRO M21 has an accessory for it called the washout remover that is a little illuminating light that attaches to the fiber optic and can be adjusted for brightness. This really eliminates the whole point of the battery free selling point though. Maybe look at the Leopold Delta point Pro it is motion activated as well and uses an LED to illuminate. It can be had with a great for CQB and precision triangle reticle or a 2.5 MOA dot. 

aimpoint  NV compatible even if you aren't thinking that direction right now.

Unless you want a smaller footprint or like the micros better than full size, Aimpoint Pro first followed by the Trijicon MRO. Toss the others, Trijicon RX06 & RX34 are nice but there is a chance of reticle washout and you can't adjust the brightness. Forget the Meprolight, I'm sure they are good optics but if for any reason you have to deal with customer service, dealing with the Mako Group is literally as painful and annoying as pulling teeth. Aimpoint customer service is incredible, in my experience they have even replaced optics I got in trade/wasn't original owner where I got screwed (i.e, stripped holes in a T1 micro body and the trader didn't disclose that information to me) and they said no worries, we will just give you a new one. In short, Aimpoint anything > the rest

The PRO for that list

Home defense? Point and fire. Pew, pew, pew.

Anyone one of those with a set of fixed BUIS.

Aimpoint PRO.  Cheap, reliable, durable, a little heavier than your micro sights but thats not a big deal IMO.  And yes, I find the MRO to be ass ugly too haha.  Looks like a hokey toy submarine sitting on top of your rifle.

Thank you for putting into words what I'd consistently been envisioning. That or one of the pipes from Mario.

Went and looked through all of the EE listings for New/Used, WTT and WTS, and found an RX06 for a really low price, so I'm going to go ahead and give that a try if it goes through. If it doesn't work out, I should be able to flip it for near the same price and I'll pick up a PRO. Added all the comments up between this and a reddit post and the PRO was the most overwhelmingly recommended one by a huge margin (7 for the PRO vs next highest of 2 each for the MRO/Micro/Tru-Dot). But for less than half of my expected budget and $60-100 less than any of the PRO's I came across, I just about couldn't not give the RX a chance.

Home defense:

Duty grade, motion activated, always ready, small footprint, lightweight, excellent FOV:

Leupold Deltapoint Pro with choice of 2 MOA dot or 7.5 MOA triangle (my choice).

I've always seen the RMR's touted as being nigh indestructible, but I haven't really seen anything on the durability of the Leupolds. I'm quite a fan of them due to their triangle reticle, especially after handling one, but I just haven't seen a whole lot on them. How do they compare to the RMR, and are sights with that small of a window a hindrance compared to the larger and more forgiving window on rifle-specific sights?

The window on the DP Pro is much larger than RMR and Aimpoint Micro.  As to durability, the window is shrouded in spring steel.  It was selected with Aimpoint T2, and MRO for the final cut in field tests by USSOCOM to replace EOTech.  We don't know if those trials are concluded.

http://soldiersystems.net/2015/11/09/ussocom-evaulates-replacement-for-eotech-sights/

Mine seems very rugged, but I'm not sliding down mountains in Afghanistan in combat.

i'll second that. batteries and electronics follow murphys law.

My go to is the H1 or H2 with BUIS's. I don't need nor want NV and because of that the H series being slightly less expensive appeals to me.

Hm. This is looking more and more intriguing, especially since opticsplanet had then for about the same cost as a PRO. It'd need a mount, but it's still better than a lot of other options. I'd only really looked at the micro reflexes for pistols before.

Aimpoint PRO vs Deltapoint, which would you think is more effective and viable for a HD carbine?

I trust my DP Pro.  Excellent visibility around the optic.  No knobs, dials or other protrusions.  Screen is clear.  No tube effect. Motion activation means instantly ready.  I'm close to three years now on original battery.  Those who carry them daily are seeing one year.  Far lighter than the Aimpoint Pro.

I prefer the Aimpoint Micros over the PRO but its hard to beat aimpoint durability. The MRO may be just as durable but has not been out as long and therefore there's not as much data for it.

I really like the field of vision that you get with the MROs tapered shape. Whereas with the Aimpoints you get a slight "looking through a tube" affect.

Of your choices I would go Aimpoint PRO then MRO as a very close second. The minute aimpoint makes a 25mm RDS I would probably sell everything and go exclusively to those. The 25mm size of the MRO is the sweet spot.

Of your list, Trijicon.  Got one on my duty gun.  Personally?  Look at the Vortex Razor Red dot for an awesome lo pro style open style sight.