Great discussion. One think I didn't see was the time it takes to dry the suit. A tri-lam will dry MUCH faster than a neoprene, crushed or otherwise. This is real consideration for me. Also the Tri-Lam is easier to get in and out of, which I appreciate when shore diving and having to sit in the car in between dives in January.
I wear more thermals underneath, but that's what keeps me warm when I take the suit off on the beach and it's 10F and snowing.
As for custom vs's stock; once you've nailed down the manufacturer, get their info on sizing and measuring. Perform the measurements as if you were going to order a custom suit and then compare your measurements against the stock sizes. If it's a good fit fine, otherwise pay the extra and have it cut to fit.
Zippers: A man can use a relief zipper, to quickly relieve that pressing urge. If you can't, consider the front entry zipper as a very good thing.
Seals: I only want latex thank you.
Talk to divers in your area that dive in the same conditions in which you want to dive. Some divers dive dry suits in 55 - 70F plus. Others may be diving in less than 40F. Wreck and Cave etc...
I like DUI and I like their Rock Boot system because most of my diving here is from a rocky shoreline. However the rock boots generally will not fit your "current fins". So more money there.
And don't forget to figure the cost of the underware into the cost of the suit. I like the fact that with a tri-lam, I can vary my warmth as needed, but make sure you figure your MAXIMUM undergarments when determining the size or fit of your suit.
My .02 cents.
