If you mean "are we still using the same style of sticks now that we used back in the day," then... yes and no. Most arcades in the US used Happs and Happs knock-off parts (Einstein's used Happs while it was still around, for example). If you played at an arcade years ago, you probably played on Happs.
UFO uses sticks/buttons from Japanese manufacturers, primarily Sanwa parts (I think a few setups have Seimitsu parts?). There isn't really a cycle of styles or anything, Japan has been using Sanwa/Seimitsu parts since like forever and since UFO is a Japanese style arcade, it only makes sense to use Japanese parts.
...plus it's not like there's much demand for American arcade parts these days.
As for adjustment between the two, maybe it would be an issue if you had been playing exclusively on Happs sticks for years and years of regular playtime before switching to Sanwa/Seimitsu. If not... dunno what there is to "adjust" to other than playing on sticks in general.