Water stones are great for your standard variety steels... Can be a little time consuming, even all but worthless on some of your higher end hard carbide varieties...
Norton is the best all around in my opinion, without spending a fortune, and they'll handle most of your modern mid level stainless steels pretty well also without premature wear or overly extended time on 'em (elmax, cts-xhp, s30v, s35v, n690/vg10, etc)... They're more true to their grit rating as well, where a cheaper stone will still work fine, esp. On your basic varieties, in my experience they wear and warp quicker, requiring more frequents lapping (leveling), and also their grit performance seems to about half, maybe just over that of a Norton, so keep that in mind.
-Ie. Two cheaper Brands I have used, and actually still have around for basic stuff, Taidea or a Horntide 1000 is more like a 6-800 hundred Norton, 2000 is more like a Norton 1000, and 8000 is more like a Norton 5 or 6k at best. (Better then the 4k, but certainly no where near the 8k).
The 4000/8000 combo stone is the most popular, and if you're like me and don't really let your knives get too dull in the first the place, that can really be all you need to maintain a very keen edge.
1000 is nice to have, lower is good for reprofiling a funky edge, higher is good for a more polished micro edge, (but 8 is still pretty nice with a strop).
If you go with a cheaper brand in a 4000/8000, you can certainly still get a nice cutting edge, but for a really fine edge I'd suggest buying a cheaper 10k or 12k also, as it will probably be similar to an norton 8k. You probably won't need anything lower provided your sharpening an existing edge, not reprofiling a completely chewed up one.