I'm not familiar with the Mares computer but have had a few Suuntos. I would not want to wear one as a watch. Not only are the Zoops too large for that, in my opinion, but after a few minutes the display turns off and has to be turned back on by button press. It then takes a few seconds for it to go thru its start-up process. Just seems like too much trouble.
I now use an Oceanic OCi which has a watch size display. It is slightly larger than a standard watch but not by much and the display is always on. And although the OCi is smaller than the Zoop, the display image is only marginally smaller. The OCi is an air integrated computer but you don't have to use it as one (I do). Oceanic computers run a dual algorithm, one conservative and the other a bit more liberal.
Last I looked, the OCi is priced below $500.00 for the computer. You can always add the transmitter later if you want AI.
I'm sure there are other dive watch computers on the market, but the only other one I'm familiar with is the Shearwater Teric. It is probably the best one out there, but is about double the price of the OCi. It is also AI and uses the same transmitter as Oceanic.