if you go 3/4" MDF, your will save money on your T-molding (if you go that route). All other sized are 'special'
I dont think plywood is as easy to cut the slot for the T-molding as MDF, but you get a LOT less sawdust.
MDF is strong enough. So you don't have to worry about that.
I went MDF and am happy with it. I didn't paint, (vynal) and I didn't have to sand before applying. If you go with a lexan top, I don't think it will matter at all. You might want to get the better grade plywood if you are going to put artwork between the lexan and CP.