I'm on the process of trying as much equipment as I can before moving on to buying my own. Since I intend to dive a lot in the Mediterranean, I was considering the possibility of buying a semi-dry suit, hoping it'll be good for the Mediterranean in the autumn/winter and for colder climates too, with some sort of undergarment too. I'm also hoping I'll be able to use it in the summer, letting some water inside now and then if I feel it's too hot.
Anyway, I'm still trying all types of suits (except for dry suits, which I haven't used yet). I had a couple of dives in a lake two weeks ago, on a day which was specially cold for the time of year. Everybody around me was wearing a dry suit, and I was the only one to wear a semi-dry one (a Hollis Neotek) with another layer below, and I must say I felt perfectly comfortable temperature-wise (I've never been too sensitive to the cold). And although I've made a habit of writing down the equipment I use and how much I like it, I completely forgot to ask what it was I was wearing under the diving suit (it was the first time I wore something apart from my swimming trunks). I don't know whether it was a rash guard, or some sort of thermal protection (I don't even know whether rash guards also provide thermal protection or not!).
Can you recognise it from this photo? Unfortunately, I haven't got any from the front where the brand can be seen.