I've been using Patreon for over a year now, so I'm already nice and established and building a community there. Yay!
I did have plans to eventually migrate my supporters to the Tapastic Support Program since I liked the TSP system better, however, I never got around to doing that before they announced the end of it (thankfully).
I use Patreon because it's seems to be the most well known/trusted support site. When you mention Patreon to someone, they aren't confused, they pretty much know right away what the site is and it's function since so many indie creators use it.
The site also accepts Paypal which is a huge plus and takes care of VATMOS for the artists.
There are feature that I wish Patreon had like scheduling posts and a way to more easily offer rewards for accumulated support backing like what TSP had, however, the site does serve it's purpose and is funding my comic making career. (way better than nothing ;D )
There are also ways to make you Patreon resemble your TSP page. Like Kit & Cat's page is my absolute favorite. (gives me so many ideas on how to improve my own page)
Fany's is another gorgeous page I'm drawing inspiration from
I've seen a few artists get ready good conversion rate from offering a special thank you reward to supporters that make the switch from TSP to Patreon (or whatever site you eventually choose). Or, in one case, an artist offered a Milestone Goal of unlocking 2 pages per week update for the full month if met. They got it and then some.
I guess another plus to Patreon is a lot of creators from Tapastic are moving there, so announcing it to Tapastic readers will be pretty familiar as they've heard the same announcement from other creators.
Either way, in whatever support backing site you eventually choose, good luck to all in this time of change and keep us posted on how well it's going.