I do like a good burger. I've tried most of 'em and Byron is my go-to Burger of choice. I like the fact they are not too flash or clever – no foolish brioche buns or pulled pork here, just an honest, juicy burger, served medium, with a proper bun and straightforward accompaniments.
If I were to offer constructive criticism, I would prefer a slightly smaller bun and certainly more relish – you can barely detect the “Byron sauce” they put on, requiring judicious use of ketchup and American mustard.
Sides are variable: french fries are fine, I like the onion rings (mine have always been crispy) and the courgette fries, but the skin-on chips and the maccaroni cheese are to be avoided. In terms of drinks, if you're not ordering a malted vanilla shake, then you need urgent help. Damn fine milkshake.
Service is usually quick and efficient, even when it gets busy, but there is a distinct lack of atmosphere, and they do feel a bit “corporate” (I've been to Kings Road, Gloucester Road, High St Ken and Westfield). However, for a burger joint, that's less of an issue for me – I don't go there for a long luxurious meal, I go there for a cracking burger, fries and malted vanilla shake and expect to be in and out within the hour.
It may not be as “cool” as a Bar Boulud burger, but it's a lot bigger and only costs £7. In terms of upscale burger chains, it beats the rest hands down.