I have used Hager for years and years and find them to be completely reliable in terms of switchgear build quality and lifespan. I used to work for a commercial installation firm and we installed lots of it due to it being a council specced brand and having lots of council work.
I have used BG several times before and found issues every time I have used them. Broken terminal threads, RCDS not meeting trip times, main switches splitting when tightened, general poor quality, so decided long ago that they were a brand not worth bothering with to me.
Back when I was installing dual RCD insulated units the price difference between Hager and BG was less than ÂŁ20 so wasn't even worth considering penny pinching. From personal experience it's a McDonalds or steak and chips scenario.
When I moved to installing RCBO as my only option, I found Hager far too pricey so looked around for other brands. Not from wanting to not use Hager, but from the understanding that most others would be undercutting me using BG/MK/Cudis/etc.
I'm currently getting prices for Hager from local sources as the prices have come down a little and I'd like to start offering them as an option to customers again. Still coming out pricey though.