I don't know how fancy you want to get, but the one you mentioned has many features than I ever needed with my intervalometer.
It seems to me that if you don't know what to look for, your needs will be pretty simple, like my needs - you just need to take photos on a predefined interval. And I think almost all devices will satisfy this need perfectly.
One feature that I like is the ability to manually release the shutter 'during' an automated session. I found it useful when I wanted to include more photos of a particularly interesting moment during making a time lapse of a trip.
SO if it is not the set of features, what else is important?
Battery life - most devices offer satisfactory battery life, but on a remotely triggered model it may be shorter than on a cable model. Can the batteries be replaced? What size does it use? How easy it is to charge / replace batteries?
Quality of build. Are the contact points metal or plastic? Are connectors solid and will they not break due to frequent use?
Does it get a lot of bad reviews online? Are there known issues that people frequently report?
Make sure you are not paying too much for a brand model. I use a cheapo intervalometer that I got for ~$30 bucks and I have made many time-lapses with it. It never failed.