We had our boiler replaced just last week by British Gas, a Worcester Bosch 15Ri. Both the engineers that came to install it had nothing but praise for them, and the service engineer that fixed our old boiler highly recommended them too.
The service engineer said stick to either Worcester Bosch or Valiant, but Glow Worm are okay too.
The one we had replaced by the Worcester Bosch was a Glow Worm, lasted well.
We replaced the glow worm in ours because it was forever breaking down...
And every plumber/heating engineer we spoke to said they wouldn't use a glow worm for a foot rest, they are pieces of junk lol.