Most interfaces will work fine w/ most music computer systems. Most of the problem comes from latency, which is how long it takes for sound to come into the computer (for recording) and then back out (so you can hear what you recorded). If you have over 10 ms of delay, it can really be a problem. However, most interfaces today have the ability to send the track to be recorded directly out of the interface, too (thereby skipping the latency). So all is well.
All modern music interfaces cards will perform as above (or every one I've heard about), so you are good to go. When you read user reviews on a manufacture's site etc. you usually get comments from people that have had problems, so the unit looks like trouble. Fewer people write in to say it works great and "I didn't' have to think about it." Since different PCs are stuffed w/ any number of choices for components, nobody can test all the variations until the public gets ahold of it. You might be the unlucky 1 out of a 100 whose computer just won't work w/ a specific unit and driver. The solution is to buy from a retailer who lets you return your buy for another, similarly-priced unit which should work - 99 out of a hundred times.
At this point, using SONAR, I'd check out the TASCAM units (Gibson owns Cake and TASCAM so everyone uses those at the office). TASCAM is as cheap as anyone on the lower end, and has the best bang for buck in a couple of categories. One good thing is that TASCAM (never known for great drivers) hired their own driver writers and their drivers work across the range of their newer products. Updates seem to be coming out regular-like and each iteration seems to have less latency. And since TAScAM is coming out w/ new units, it looks to be a good bet. See the latest Tape Op
http://tapeop.com/ for a review of their 20x20 unit.