Over the years I think I've probably had them all, EVC, DSBC, AVC-R etc and all do the same job, control boost, so I figured I'd give the HDI a go, it doesn't have a huge brand behind it but I've also learnt over the years that doesn't always guarantee quality.
I read round a bit and they seem solid and work well, so I've bought one anyway, lets see how it goes, bargain price as well

I'll post back up once it arrives and review general build quality etc