So, my next project will be a KISS midlength.  I've settled on most of the details, but can't quite decide on a rear sight.  Since it will be battlesight zeroed at 50 (then 200) yards, I'm going to avoid rear sights with elevation adjustment.  Since I don't plan on putting an optic on this rifle, I'll be avoiding a folding rear sight.

This leaves me with 2 candidates for a rear sight:
1 -- A standard A1 upper.
2 -- An A3 flattop with a LaRue BUIS added.

I've settled on a Del-Ton kit with chrome-lined bore.
The flat-top won't cost extra, but I will need to buy the LaRue (~$89 + shipping) if I go that route.
The A1 upper adds $30 to the cost of the kit.

I guess what I need is for owners of either type of sight to give me the good/bad points, as they have become clear to you through using them.

Thanks.
D14

The LaRue offers a more practical sight picture for long range shooting (I use only the peep sight, except in utter darkness).\

If you're planning on never attaching optics, then the A1 makes perfect sense.  No need for empty rail space if it's going to go unused.

Otherwise, you'll be a LOT happier with a flattop configuration... again, the A1 seems like a better choice if you're not going to add optics.

Quoted: The LaRue offers a more practical sight picture for long range shooting (I use only the peep sight, except in utter darkness).\ If you're planning on never attaching optics, then the A1 makes perfect sense.  No need for empty rail space if it's going to go unused. Otherwise, you'll be a LOT happier with a flattop configuration... again, the A1 seems like a better choice if you're not going to add optics.

+1, with parts I'd like stressed in red

HOWEVER, be aware that if this is your only AR, you WILL get the urge to add optics.

If this is going to be a 2nd, 3rd, etc. rifle then go with the A1.  You can't beat it for simplicity and reliability.

So, if this is your "next project" I'm assuming you already have at least one other AR?  

I did a flat top for my first AR, but for my second, I wanted a KISS type rifle like you, and went with the A1 with a Bushmaster superlite barrel.  I really like this rifle. It's all a carbine should be---light, handy, accurate, and KISS.  Even put an A1 handgrip, and a factory Colt 4POS fiberlite stock, and a tear drop forward assist.

I haven't shot it enough to really wring out any negatives.  The one thing I'll say is the apertures on the A1's are smaller, as you know, so if you want the option of a larger ring, you can put A2 apertures on it and cure that.

I think the lack of rear elevation is really no big deal at all, unless you plan on shooting 500yds with it or something. I did like you're planning on doing, and sighted it in with a 50 yd battle zero.  I find I shoot better with this rifle than with my flat to w/a carry handle and A2 sights.

If you already have a flat-top AR set up the way you want, there is no reason at all NOT to go with the A1, I think you'll like the lightweight and simplicity.

I built a 16" carbine with an slickside receiver.  
I love it.
Light, fast and handy, even with a heavy (.750) barrel profile.  
Used an FA recevier, DTI/Wilson barrel and the Young's NM BCG from Dennys.

I drilled out one of the apertures to make it a ghost ring.  Sighted the other aperture using the Improved Battlesight Zero method.  It's a great rifle if I do say so myself.

Simple is good sometimes.  I say go for it.