I had the Taurus suit and it's a great semi dry. It's a top quality build with top quality materials. The key to a semi dry keeping you warmer than a regular wetsuit is fit and seal. You do not want a suit that has anything other than a snug fit. My experience with the suit is that it was reasonably comfortable in 45 degree water for a 50 minute dive. Surface intervals can be your undoing if you cannot get out of the suit to warm up. If surface temps are warm you'll probably be ok keeping the suit on, but keep in mind that a wet suit, semi dry or no, acts like a mini refrigerator topside since evaporation removes heat from your body. If you can't warm up on the surface interval, your second dive is going to be less comfortable.
Think this through carefully, you might want to think about a dry suit if you going to be diving cold water. It was the surface interval issues that put me into a dry suit.
There are great deals out there. I got a DUI TLS 350 with lots of extras for $900 and it had never been in the water, it was a brand new suit. The Taurus brand new was $800.
Mark