You get what you pay for.
It's not so much the case now, but quite a while ago, if you bought a cheap trials frame, the geometry would be utter shite. Onza springs to mind, in roughly 2001-2003 basically all thier frames rode quite badly compared to what was also on the market at the same time, then they sort of caught on and decided to copy Koxx with the Levelboss/T-pro and then Zoo! with the Pitbull/T-Rex and the rest is history, now we even have Zona and all that. Even still, why do they still make and sell the T-Bird? They should just put all the cheaper parts onto a T-Pro frame and get rid of the T-Bird all together.
Could be slightly biased, as I'm not a mod fan