I've tried all the weathers, but when I tried Sun, I stuck with it and never looked back.
Simply put, the Chlorophyll users are bloody awesome, and Ninetales is pretty sweet too if you pair him with Wobb to take out the other weather starters.
Stacking several Chlorophyll users on a team seems to work out pretty well for me, and I have DD Scrafty as my glue to the sweeping core. I personally find that Sawsbuck and Tangrowth are the best Chlorophyll users, simply because they're very difficult to wall when you pair them up, especially if Scrafty is with them.
I like Sawsbuck the most because he not only hits ridiculously hard with Return (easily solving the Dragonite problem since he does not take Return well at all, especially after Multi-scale is deactivated), but also that after a SD, literally the only things that switch in on him safely are Skarmory and Chandelure (who's screwed if you carry Nature Power). Also, none of the weather starters can switch in directly against him because T-tar gets killed by Jump Kick or Horn Leech, Abomasnow can't take a Jump Kick, and Politoed dies to Horn Leech. Having 95 base Speed is also nice, because it means that even when he's Adamant, he's able to outspeed damn near everything, and after a SD, OHKO/2HKO everything. I also have a hard-on for Horn Leech, because absorption moves really make the game hopeless for the opponent once Sawsbuck is set up.
That's why I also like Tangrowth, because unlike Venusaur, he can use Giga Drain with Chlorophyll, and unlike Lilligant, he doesn't have the defenses of a wet paper bag (at least physically). He also doesn't take a ton from Scizor's CB Bullet Punch (I believe it's 40% or so, which is pretty good considering he's investing nothing in his defenses).
When I was at the top 20, I started noticing a lot more Sun teams, so it seems that while a lot of newer players think Sun sucks, a lot of experienced players seem to think otherwise.