I have this suit for use in UK.
I think it is great! I'm not too sure about drysuits which are like great saggy bag and people wear all their day clothes under it - it is too much like normal life.
I like the Mares semi-dry because it keeps me warm through most of spring/summer/autumn in the UK - I think I have used it down to 12 degrees C. But I was going to buy a chillcheater to go underneath for late autumn for the following reasons:
1) It is off putting if you take the suit off inbetween dives if the wind blows as it is very cold to put it back on!
2) I can sometimes feel a little chill through the cross shoulder dry zip - especially if I reach my arms out in front of me whilst under water - so chill cheater would solve this - as it is thin enough.
3) Chillcheater does not wick water off your skin - so should help prevent some windchill whilst you get changed inbetween dives.
4) Chillcheaters are made to measure so should fit nicely under the semi-dry.
www.chillcheater.co.uk
www.chillcheater.co.uk/products/shop.asp?cid=4&p=1&pid=911
I find my semi-dry great - as I feel more at one with the sea and my surroundings whilst diving - and not lige a great bag full of air!
Hope this helps - PS Do'nt make the mistake I did and lube the dry suit zipper with the usual beeswax - it really messed up the zipp - I had to clean with detergent and lube with silicone grease - now it is Perfect!
PPS used the suit in Egypt -red sea - most thought it was cool looking - and performed well at depth (40m) where my friends got a little chilly in normal wetsuits.
Have fun buddy!