gamespace lets you select multiple vertices, edges and faces by default, I don't understand where the problem is. Personally I found it to be more quirky than truespace, which just happens to be my app of choice. I found it to behave more like the MOD tools of late, but still retaining the TS feel, the orange boxes around chosen tools is a bit lame, i preferred the nice blue effect.
All in all though GameSpace is really good, especially the free version as you can still make a fair amount of decent models using the 650 poly limit that has been imposed. the lack of (usable)render functions is not a problem if you only want to model low poly characters. and that's what the package is all about, so it's a win win situation and all for free, groovy.
regards, geecee3