Another Chatime, this time in Chinatown, London
Chatime, which is one of the best of the newly opened bubble tea places (and with branches all over Asia), has a new branch on Gerrard Street -- any comparisons with the Soho branch?
P.S. Cuppacha nearby is also pretty good. Probably a slight notch down are the 2 places on LIttle Newport Street, just next to Baiwei.
Do note that I mentioned best of the newly opened places rather than just best.
But to address your question, it's like saying best modern British, best donut, best Peruvian etc... Cupcakes or bubble tea aren't inherently more or less gimmicky than modern British or donuts or Peruvian. There are good and bad versions. There are people who will use hype to market them, and there are people who fall for the hype. But the presence of hype or bad versions doesn't mean that the entire category is bad.
The way around all of this is to simply try stuff and make up one's own mind about a particular rendition, and sample as broadly as possible. Look for the flavour of the tea and the texture of the tapioca pearls, among other things.
For more info about bubble tea, might be worth looking at the General Topics board -- have a look at these for example (cursory search, probably more):
That place Bubbleology is awful awful bbt. Loving this new bbt trend -- BBT was super popular in Vancouver when I was in high school in the 90s.