Be sure it will handle Nitrox. That's something a lot of people end up diving eventually.
Check whether any unit you are interested in has user replaceable batteries.
I like the option to download dive data from the dive computer to a regular computer. This allows me to log my dives without bothering to write much down soon after the dive. Especially with the camera rounding out my data collection for what I saw and when. Some computers require additional purchase of an expensive download cable. But this is a feature worth having in my book.
If your computer is air-integrated, then it can record start & stop air pressures to make logging dives even more automatic. Air-integration does tend to add cost.
Wrist vs. gauge computes are a big deal to some. An air-integrated wireless wrist unit is likely out of your intended price range, but lets you glance at your wrist without messing with a console or SPG. If you get a non-AI wrist unit, you've still got the SPG to keep up with.
I see the computer Chrpai linked for you have the option to buy a wireless transmitter and PC download kit separately, after-the-fact, so you could spend $250 on sale for a nice wrist unit, AND add the wireless AI and download capability later if you wanted to. I'm not familiar with that computer, other than that Hollis is a reputable name brand in some other things, but I'd seriously consider it.
Richard.