Still need to check out The Grazing Shed in Cardiff and Atomic Burger from Bristol where I'm from. I've heard great things about both. I did go to Cardiff's Gourmet Burger Kitchen and it was pretty decent, though regrettably I had the thin fries instead of skin on wedgie style ones. The burger meat itself was nice, but the one I had had too much blue cheese and I found it kind of off putting. It was really busy too the place itself isn't very big, there was like a line of people waiting for a seat when I was there. I don't think I'd rush back there but it's in no way bad or anything. Honestly, a good weatherspoons burger and a pint for £5 is never a dull moment, very cheap and you get a decent burger for the price imo with tasty chips and a drink. can't really fault them.
In the last few weeks I've had both my first Five Guys and first Byron.
Five Guys Didn't actually know what to expect as I had never really looked into it before, but was hungover and in Leicester Square so decided to go for one. Was unaware that it is essentially a standard fast food style burger. Nice that you get to choose what is on top, great portion size on both the burger and chips but i couldn't help but feel it ended up being pretty expensive for what it was once i had got chips and a drink as well. Made sure to get a couple of refills... Would go again, I imagine it would be great on the way home form the pub, but would probably just stick to the burger and hold off on chips/drink.
Byron Had heard good things about Byron burgers. Opted for the summer special of the Freddar Dawg, which is essentially a patty in a hot dog bun and plenty of cheese, bacon, pickle etc. I thought the patty would be shaped to fit the hot dog bun, but it was actually just cut in half then slotted in to fit. Was a bit of a novelty bu the burger was very good, asked for medium rare and it was nice and pink in the middle. The sides were good but not amazing, nice selection of beer as well. Would go again, especially as a couple of their special burgers (the B-Rex i think?) sounded really good.
Also it is apparently National Burger Day on the 27th August and loads of places are doing 20% off to celebrate, you can find where is doing it and get your vouchers online! http://nationalburgerday.co.uk/search