I like the Itallian Super Tigre's, do not have any of the Chineese ones yet to make judgement on.
As far as a 120 size engine, Hands down it is the Thunder Tiger. Ultra reliable, very powerful and last forever. Second choice would be the Webra 120, just as strong and reliable as the TT.
For the 90 size, I would choose the older Italian Super Tigre 90 and the MVVS 91. Both great engines and very difficult to wear out. Both have exceptional carburation.