Hey Shelly,
Henderson does make a great suit having owned a few over the years. I also am a fan of Waterproof and Fourth Element. Reason I like Waterproof is because it's very flexible at the joints, very stretchy, and I love the seals. It has a double seal system like semi dry suit. The outer neoprene has zippers at the ankles and wrists making it easier to take off. The second inner glide skin seal keeps the water out and mates well with your skin, gloves, and/or boots. Scubapro also makes a good suit.
I've also heard the same thing Suzi has about the stretchier the neoprene the faster it will start to compress and lose it's thermal insulating value. I don't know if that theory has been tested yet and either way can't imagine it shortens the life of a wetsuit by that much. Even if it does, would I rather have a wetsuit that lasts 10 years and I struggle to put on each time or one that lasts 5 years but goes on like a breeze?
Most major wetsuit manufacturers now tout some version of stretchy neoprene. And it will help with putting on and taking off, but most importantly is it will help with fit. It's good that you are finding out which are some favorite brands, but then the absolute key is trying them on and finding that perfect fit.
You want a fit that is form fitting and hugs the contours very closely, especially in different positions. When you put it on, stretch your hands over your heads, see if pockets of air form in spots around the small of your back or anywhere else. You want the suit to stay up close to the skin as you move into different positions. Some space is ok as the purpose of a wetsuit isn't to block out water, rather to trap it and let your body heat warm it up creating a layer of insulated water between you and the neoprene. That's why neck, ankle, and wrists seals mating well with you skin is important, it limits the water "flushing" in and out of your suit exchanging the warm water in your suit for cold water outside your suit thus getting you colder.
If the wetsuit doesn't fit well and you have large pockets of air created as you move around it will act like a pump pulling in cold outside water when the pocket opens and pushing out warmed up water as the pocket collapses. So fit is absolutely the most important thing. Then make sure the seals around the neck, ankle, and wrist are flush even when in different position. Pay careful attention to the neck seal as sometimes it can pucker open a bit when your arms are raised over your head or even when tilting back your head. That of course would let colder water to rush in. and cool you down.
Also agree with George that a dive skin comes in handy as it makes putting on and taking off of a wetsuit much easier. I get cold easy too (Go Team Warm Water Wussies!!) so I wear a lavacore base layer under my wetsuit so that gives the same result as a dive skin in terms of putting on a wetsuit.
Lastly, look at the seams, the major brands like the ones that were listed so far in this thread all have very good seams. You are usually looking for some kind of blind stitched or flat lock stitching, ideally either taped over or "welded" over so that the threads of the stitchign don't dig into you skin and leaving tracks all over you. And more importantly, good seams mean less chance of water seeping through the seams and contributing to "flushing" and decreased thermal protection.
You'll do great with any of the wetsuits listed and there are I'm sure several other very good brands. Avoid surface water sport specific wetsuits like surfing ones because some of them are not optimally designed for diving. Ultimately, its all about the fit.
I could make specific recommendations in terms of best fit for women, but then I'd have to explain how I know that information and I'm not going down that road
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