Replacing Combi Boiler Vallient v Glow-Worm

[thermalthelma]

Looking to replace my 20+ year old combi. I can easily see that Worcester Bosch are the Olympic winners on nearly every site I've gone to BUT, what about Vallient v Glow-Worm - I've been told they're 'identical' apart from outer casing and made at same factory with same components [but with a difference of between £200-£300 ! ] - anyone out there that can clear this dilemma up for me ?
Thanks

 

[ollski]

vaillant and glow worm are owned by the same company but don't use the same components. I have personally got ultracom2's with weather compensation and never had a fault with either in the last 18 months.