Depends, what kind of a stroke do you have? There are pretty much 2 primary types, an Arced path and a straight back straight through. If you have more of an Arced path you need a putter with toe hang to match that stroke. Toe hang is like when you see what people refer to as the "plumbers neck" style putter. The toe points up in the air slightly, and the hanging weight matches your stroke. Varying neck styles and head styles suit different types, with face balanced putters suiting more of a straight back straight through stroke. Mallets with a center shaft, long plumbers neck, and a couple other styles are more face balanced.
Pretty much though, it all comes down to whatever feels best for you. Test THOROUGHLY, I have found this out the hard way haha. Find something you REALLY like. The feel, the weight, how the putter reacts with your stroke, yada yada. Try to quantify all these factors while you test putters, if possible get it out to a real course/green so you can ACTUALLY putt with it. There are extensive putter fittings, that can cost from a small amount of money to a very large sum of money. Yes that will get you the best putter for your game, but is it really worth it for YOU is what you need to decide.
In terms of brands, the brand of putter really doesn't matter. If you sink the putt with a 20 dollar walmart putter better than a 5k tour scotty, well then that 20 dollar walmart putter is better. In general though, Taylormade makes a decent lineup, Scotty Cameron, a couple of lesser known brands are Bettinardi(These are absolutely amazing) and Piretti. All those companies do fantastic work. Scotty, Bettinardi, and Piretti make what you would call a milled putter, where there is no insert in the face, its all milled metal that has a very distinct, crisp feel that is great for distance control. Taylormade has inserts in most of their putters, and varying types of inserts. Their typical AGSI insert currently I find is pretty stiff, gives good response but I'm not a fan of the feel. The Japanese model of the Taylormade Itsy Bitsy spider that I have has a carbon fiber insert, which is softer, but gives me the perfect feedback and I have the best distance control I ever have with it.
Scotty, Bettinardi and Piretti are all around the $300 mark, where as Taylormade has a very wide range of prices, but are typically around 80-180 I believe.
If you're looking for a good feeling, milled putter at a bargain price Cleveland has a great product at about the 70 dollar range. The metal is a bit different than the aforementioned milled putters, but unless you have a great touch, you wont be able to tell a difference. Nike and Ping also have good putters, but I dont have much experience with those.
IN SUMMARY. Start off by just thinking about your stroke, do you have a slight arc or are you straight back straight through? You can use that to initially narrow down selection a bit, but if you're trying the putters that are oriented for that and they all feel terrible for ya, then try the face balanced ones. IF POSSIBLE, get it to a real course to see if you REALLY like the putter. Lastly, once you get a putter, STICK WITH IT. I am a massive hypocrite when it comes to this, but the putter I have now I will definitely be sticking with it. Keeping the same putter for an extended period of time allows you to become accustomed to it, read its motion, develop the feel with it you need to really sink your putts.
If that didn't help let me know, I'll try to narrow it down a bit more based on what you're really looking to go after. Basically, not any single putter is better than another. Its whatever putter works best for you, because going from one to the other they are basically the same. There isn't a whole lot of difference besides weight, headshape, and shaft placement.