I like the concept. I'm just not sure if it flops around to much.

I have this version:  http://www.skdtac.com/HSGI-UDHP-Holster-SKD-p/hsg.311.htm

It certainly does not flop.  The holster rides high and is very secure.  When someone asks me for drop leg suggestions, HSGI is the only option I give them.

Thanks for the info. Glad to hear it doesn't move. Have you tried out the small panel for mag pouches also, does hold as securely is the pistol drop leg?

I've used the Costa Leg rig for a couple days while I had it.  When properly adjusted, it didnt move or shift.  Rides nice and high.  I had 2 pistol mags, 2 rifle, and a flashlight on it, and ran around all day, and nothing fell out or lost tension.  

I'm actually considering the all MOLLE version so I can customize what I want on it.

I have had a HSGI drop leg holster for maybe eight years now.   I got it for carrying a pistol when hunting.  At the time it was best out there.  I especially like the mag holders and have purchased four more in the last couple of years for a mini chest rig.  It rides higher that the spector holster out  of the box (before mod) that I am using with my current pistol.  I like the construction better but it is two snug for my XDm, being sized for a sig.  It doesn't seem like there is a good way to mod it either to allow a larger pistol.

edit to correct spellen

Thanks for the response. I think I'll pick one of the modular ones up myself. I have a couple rifle/pistol taco pouches I would like to move as far forward as possible and hopefully have enough room at the back for a dump pouch. Would it be in the way if you were sitting in a car while wearing it?

I am still in love with my first gen XDs. Use a .45 & 9mm, so I may need to look at something else. Thanks for the heads up.

Are you talking about the Costa Leg Rig or the Mini Drop Leg Panel? I don't have the Costa but love the idea of a 2-point connection. I currently use the Mini Panel and I have three gripes. First, that single point connection allows the kit to walk down my leg. Two, the velco connection that goes around the belt has been pulled free numerous times. Third, because there is space for the knife, it allows for pouches on the panel to flop even though the rig is secured to the leg. This last thing is fixable by securing the middle pouch to the knife sheath.
The design of the leg strap and how it stays secure to your leg is awesome. Like I said before, if you secure the middle pouch somehow to the knife sheath it doesn't flop around with movement. I love how quickly it is to don and doff. I'm in the process of trying to change how it connects to my belt so it works more like the Costa rig.

Hmm, can't say i've done too much sitting in cars with mine on.  That's a good question.  Sorry I dont have an answer.

Talking about the costa leg rig, but good to know about the other stuff.

+1 regarding the above holster.

I do not recommend carrying mags (or anything else) on a weak-side drop-leg panel.

I have one of the early ones with mag pouches sewn on. I cut them off.

Another +1 for the HSGI UDHP.  I bought one of the originals with the buckle but had a strap made like the SDK version.  Comfortable and you can swap out the inner holster to fit your needs.  

IDHunt

http://www.highspeedgear.com/hsgi/drop-holster-airborne-60AH.html

Above is the one that I have.  The mag pouch's are removable.

It's unclear to me from the skd ad.  Is the mount for the holster PALS?

No, the way you mount the holster is by using the screw holes on the 6004 or G-Code.  Gene from HSGI recommends marking them then burning through the nylon with a soldering iron for a clean hole.  He also offers it as a service and will grommet the holes for you when he does it.  I sent mine to HSGI and had it back in about a week.  You could also use a G-Code GTI or a Safariland MLS to mount it if you want to switch between war belt and drop leg.  I have 2 shells from a 6004 for my Sig 226R.  One for running a light and one for no light.

IDHunt