We tried both. While the nipple is the most intuitive user interface in the world, it can take some practice and trial and error between mom and baby to get in a good feeding groove. Adjusting the baby's head just a few centimeters can sometimes make a world of difference, so don't give up on it just yet. After a few weeks, my wife (mostly) breast fed, while using the pump to store and freeze milk for use when she wasn't available to breast feed (e.g. while out, working, etc).
We have to be practical here - and getting a pump is a good idea. You're new parents, you're exhausted and the baby needs to eat.
Whatever pump you get needs to operate as quietly as possible. Both manual and electric pumps make quite a bit of noise believe it or not, and you need one that isn't going to wake your baby as your wife is likely going to be using it nearby as the baby sleeps. It's not really a question of brand, but a question of how easy you can muffle the noise. Ask to see any potential choice out of the box and in operation - or the display model. Remember, you can toss a towel or something over the electric variety to muffle the noise of the motors, so I recommend them.
The other thing you want is something easy to clean and sterilize. Test how well you can take the washable parts off the pump and put them back on. Is anything too flimsy? Too difficult to fiddle with? Just look for quality like you would anything else.
Try not to let price stop you from getting something that will work very well - remember that you can pass this on to other family members as their time comes, so definitely go for the best overall quality that you can get. Just don't base that on a brand, don't buy unless you can take it out of the box and give it a good testing first!