Have a GSR box on mine. Got it in the last group but a few years ago and given I got one for my E36 too, they worked out at about 1700 for the two of them I think.
It works perfectly but it's abit function over form alright but only really an issue if wanting to show it off all the time lol.
I'll probably get a Karbonius or Streamline one when I've the new engine built.
Wouldn't be totally put off by the failures of streamlines box once they sorted the problem and Antonio fully took responsibility and offered to foot the bill of any repairs for the engine if it needed them.
One of the lads on here has one of the boxes too and Streamline contacted him straight away and he's getting another new box just in case.
I've seen an Evolve box go in shite too and think that one actually did do some damage to the engine and also have heard of Turner motorsport boxes fail.
Only ones I haven't heard of issues with are Oem csl boxes, Karbonius and GSR.