I have the same question. I may be interested in semi-dedicated, but the TCH page doesn't look competitive with the other solutions on the market. I'm not sure if I'm missing some important considerations that TCH is offering too.
Also, have you considered doing virtual dedicated server? I saw some rates on competitors that were appealing to me, and it appears that several machines share the same physical hardware, but you are able to segregate the virtual servers from one-another (Is that what your semi-dedicated already is?).
My specific reason that has me looking at semi-dedicated and comparing TCH to outside offerings is that I have "reasonable" MySQL concurrent connections most of the time (0 to 4), but have some spikes each day where many users try to do a complex query all at once, and the server fails with too many concurrent connections. The TCH helpdesk responded to me that all of the hosting plans are limited to 25 concurrent MySQL connections (From my observations, it looks closer to 30, but I am not sure of why the server would report that).
What I would appreciate here would be response to your current offerings, some key points where you offer superior value, and maybe some clues as to other offerings that you're considering in the near future.