I've played several teams since 2.0 all have their merits. I'mc urrently running GNW Tenten/Mabui/Mei/Water Main with both Heal mystery and standard attack along with the left side of the bottom passives with Lightning Tiger summon.
Typically I can dorp most people to below half on turn 1 with GNW Tenten, though there have been times where she gets interrupted/CC'd after using her ability costing me the 60 Chakra instead of Mei right off the bat on turn 2 which means I have to wait for Mabui to have her standard attack passive trigger for Mei to be usesful, but it works pretty well, helps that I'm 7th in power on my server and there is a fairly decent drop-off from 1st to 2nd as well as the rest of the top 10 to the next couple.
I've also ran Lightning/Cursed Hidan/Killer Bee/Danzo with the Root/Anbu which had quite a bit of success against everyone but the several Empress teams, their shields were too much to get through at similar power levels, though the water team was manageable. The team also had some trouble against teams that ran numerous clones, such as the Ao CC teams, as more often than you think Hidan would hit the clones with his Tags making his burst down more or less meaningless.
I've also ran Empress, by Empress I'm takling about the PB Sasuke/Mei/Mabui/Wind Main team that is very good, but it has trouble against the Fire double CC teams that are still quite prevailent running Danzo/Ao/Fire Main/(Damage dealer typically Sage Naruto) that can keep it under a CC chain until Mei is dropped and the damage from the team drops significantly. This team by sheer size of their shields does well against any other team typically though.
I've also seen/heard of numerous other variations on teams to include an Earth Blitz team utilizing 8Gates Lee that was wrecking face, Water Main/Chojuro/Darui Poison Tai teams, and many others. Water main has its' place and being equal or higher power definitely means Water has a chance, but if you are just equal power you likely aren't as strong as you would like.
Also to the person talking about the SSakura passive, you need to stack your Water Main with as much health as possible in Magatamas/Runes to get the most out of it definitely, but she can be one of the better tanks in the game with some damage to follow along.