I have my doubts about the compression tops. Although it would come down to personal preference. I trail ride in QLD heat and have spent time stuck in gullies in 40 degree heat were everyone looked like they had beetroot heads that were about to explode.
In those situations I couldn't get the compression top off quick enough. It just wouldn't let enough breeze through to cool me. My theory is, yes they wick away the sweat, but sweat is the body's air conditioning system and you need it for cooling. In cold to moderate temperature I love the compression shirt, but come summer I wont use it.
I wear a Dianese pressure suit with nothing under it and one of those Fox ventilated jerseys and the Fox ventilated pants.
As for the vests, if your talking about the ones you soak in water, they get pretty heavy. But if you put them on top of whatever you have in your esky they keep it cool for days and make your ice last longer.