In this part of the world, spearo wetsuits are usually
simple in design, no zips (cheaper, stronger, less leaks),
open cell unlined inner (for cheap, soft, close, quiet fit) -- requiring lube to put on (not a big deal but learn the technique). Usually
high waist pants or long john pants. The jacket usually includes a
loading pad, hood and "beaver tail" crotch strap (unnecessary I think & too hot "down there in the old home town" but others, including Elios, would not doubt disagree).
Colour is usually black, green or blue, sometimes part or all of the suit might be
camoflage (/"mimetec"); some claim partial camoflage works better than full camo. I like having a
nylon outer "lining" (usually the cheapest option too) -- my suit was unmarked last week but a smooth skin would have been damaged by the rocks I washed over.
Smooth skins dry quicker (my trialthon suit was smooth skin) which might be handy when using a boat to make multiple dives -- also derigeur for freedivers where looking cool & moving fast/smoothly is particularly important.
Neoprene density is not much of an issue for spearos, as generally they don't go that deep or go down for that long (unlike scuba divers). You can get
coatings to reduce/eliminate(?) the need for lube -- but lube is cheap, simple & effective (hair conditioner less than a pound a litre in most supermarkets & then used in very diluted form -- or just use water).
Spearo suit are generally
warmer than a similar spec. scuba/tri/surf suit -- perhaps because of the close (often water-tight) soft fit of the open cells, the fact that spearo spend more time nearer the surface than suba divers, and the hood (which I think makes a lot of difference).
I bought a spearo suit as I outgrew my sleeveless triathlon suit & replacement 2.5mm shortie provides only minimal warmth (ok for 2 hours in the UK Summer) -- a wetsuit was an unfortunate necessity. However, I really like my Elios spearo suit. If your scuba suit is warm & you haven't noticed any problems with it, then it is probably fine.
One more thing -- it is tempting to get an extra thick suit to avoid getting cold. 5mm is normal for UK & my new spearo suit is toasty warm even in Nov., December and January...I am a little worried that it might be
too warm for the Summer. I am glad than I did not get 6 or 7mm or the optional extra 2mm vest (I am wondering if 3mm pants might have been enough though). People say that neoprene looses some insulation/buoyancy with time/used -- so perhaps I should not worry. The other issue with thicker suits is the extra
buoyancy ... which usually means carrying more weight and
floaty legs 
[Hence my recent weight belt adventures!]. A
camo weight vest is another option to distribute weight (used to supplement a weight belt) & get that trendy partial camo look!
