While one can say, "Take out Ninetales/Politoed early," the same can be said for Tyranitar/Hippowdon. I admit, yes, they are far more bulky (especially Hippo), but the same rule of thumb can still be applied. Also smart players don't lead with their weather inducer, they save them for a bit later.
In terms of leads, I see Ninetales leads much more rarely than any other. Hippowdon is most common, and Politoed and Ttar leads are probably similarly common. Hippo is very hard to take out but is easily walled by quite a few things, so he can at the least forced to give you a free switch if not killed. TTar is very tough but that 4x Fight weakness really hurts it. Politoed and Ninetales have similar bulk but Tales has that annoying SR weakness. Sand also has the option of running both inducers. Essentially, it is often very hard to take out the other inducer when played well.
The thing about these weathers is that without the inducers, typing alone is balanced out (for the most part). Sunny Day has Fire and Grass. Rain has Water. Sandstorm has Ground/Rock/Steel. Each weather's Pokemon carry strengths and weaknesses in accordance to one another. While Sunny Day is weaker to stealth rock, theoretically it has better type coverage against both weathers. Rain also has coverage against both weathers (many Water type Pokemon have Ice Beam). Finally, Sandstorm takes advantage of the more naturally defensive natures of their typing + Stealth Rocks + Sandstorm to create residual damage.
Sun has issues with Dragon types, but against opposing weather teams it does indeed match up very well type-wise. Due to being offensive, if not packing a 4x weak it can do fine even if SR is up as well. Thanks to the mole, however, more defensive SS teams now seem to be rare.
Now that's theoretically. Moveset wise and Pokemon wise, each one plays differently. Rain is the hyper offensive weather that seeks to deal damage. Sun seeks to spread status around with speedy Pokemon. Sandstorm helps create walls, as well as cause sweeps with new abilities.
No offense to you, but I really never understood why people took Sun for a Status spreading annoying teamstyle. In Gen 4 it was certainly as hyper-offensive as Rain due to it being on a timer, with the possible exception of Jumpluff. (Manaphy and the like excepted Rain's rule too, however). This Gen rain has changed to be very slightly more balanced with Hydration abusers and permarain, and SS has become much more offensive thanks to Sand Throw and Power. Sun however seems reasonably similar. Permasun is a change, but fast chlorophyll and powerful Fire sweepers are still its bread and butter, a reasonably offensive playstyle with perhaps a tad more balance in the form of Sleep Powders of Leech Seeders.
But Pokemonwise is where it gets interesting. The thing is, people are not restricted to certain Pokemon on certain teams. A whole team of weather abusers hardly ever works, and synergy must still be met.
The interesting thing is, with all the pokemon now available, it is reasonably possible to build a team completely based on weather abuse that is also pretty well balanced, especially with permaweathers. Of course this is not the only option, but it is a possibility.
For example: A Hippowdon/Tyranitar doesn't really look like it will have much chance against something bulky like Tangrowth or something speedy like Jumpluff who can incapacitate them/an incoming Pokemon with sleep powder. Now you essentially have a free turn to switch in your own Ninetales while theirs in incapacitated. If they switch into their set up sweeper like Doryuuzu, Sandstorm is now gone rendering their potential sweep useless.
Against rain, Sun is often able to force sacrifices of either Politoed or one other poke in order to get a safe restart of the weather, due to the Grass-types' advantage. This creates a pretty big problem, of course.
Sand's inducers are ofc very vulnerable to Tangrowth in particular, but Ninetales is likewise decimated by stray EQs, SR, or pursuiting TTars. When both are run it is incredibly hard for another weather to gain the upper hand.
This is just all Theorymon of course, but still. Don't rule out the other weathers by saying Sandstorm will completely dominate once again. It's never known; the metagame still has not received sufficient testing.
Sand only dominated over Rain last Gen because there was no permainducer for it in OU. Rain was definitely the better weather, but 8 turns of it was manageable. With all the changes though, it will indeed be interesting to see which comes out on top, especially as all 3 are contenders this time around. Hail, sadly, has been left behind somewhat.