I was thinking about the Ezybox by Lastolite, but in Norway it is quite stiff in price.
I have a pair of the 24" Ezyboxes, they're quite sturdy and easy to set up. I expect the quality of light is no different from the cheap ones, but the build quality and durability of the Lastolites are very good.
I think I disagree. I purchased a 54cm Ezybox and the build quality is very poor. I returned it for a full refund after the first use. The speedring and and all the other bits are made of plastic. The speedring was such a loose fit into the softbox that it kept falling off all on its own. Pretty embarrassing on a wedding shoot when the wind is blowing and you assistant has to run after the softbox as it falls off and rolls across the grass, and collect it multiple times. I was very disappointed. They told me mine is faulty but I don't really see how that is possible as the speedring is just way too small for the softbox and some friends have experienced the same thing so I wouldn't recommend that brand based on my personal experience.
So instead, I went onto Ebay and purchased a much cheaper and almost identical version of the Ezybox (same size and double diffusion layers). http://www.ebay.co.uk/itm/ws/eBayISAPI.dll?ViewItem&item=160589932118&ssPageName=ADME:L:OC:GB:3160
It only costs £37 and for once, the cheaper Ebay special version is MUCH better build quality. The fittings are all metal and the speedring fits very snugly into the softbox. Way better that my copy of the Ezybox and I would highly recommend this as a very cheap, high quality softbox for OCF work.
Back to flashguns... The moment HSS kicks in you lose around 1-2 stops of power. Another very important consideration is that when in HSS, shutter speed also affects your flash exposure. This means when you're up at 1/2000th or 1/4000th of a second, you speedlight must be very close to your subject as the maximum output power is minimal. Forget bouncing light in HSS.
As for bouncing light, if you are in a large venue (within reason) remember you can pump up your ISO to help ease the workload on your flash, or to get more range with the flash at full power. Zooming the flash head to its maximum will further improve range but just remember the angle of incidence equals angle of reflection, so aim your flashgun at the right spot so that the bounced light falls where you want it to.