Bit smaller I know, but the Elinchrom 135cm octa is in budget, and it's awesome.
In my opinion one of the strengths of the Elinchrom system is the ability to use the deflectors in the centre of the modifiers. Using a deflector but no diffusers on the 135cm can give you a gorgeous beauty dish-esque light, or put it behind you, crouch and shoot for a result similar to a large ringflash.
The profold/bessel speedbox stuff makes this an impossibility as it folds out like an umbrella, and has a shaft in the centre. You can't fit a deflector with these.
If youre happy to spend £250, I'd really recommend having a look at the larger Elinchrom octas, they're extremely well made, stupidly easy to put up, they're beautiful modifiers.