Contrary to Globalti, I think the clothing is very good and fits me very well indeed, always worth trying it on though as you’re there.
In terms of what to look out for, the padded shorts, 700 and 520 series stuff is very good. The general accessories, gloves, socks, baselayers, etc. are also good. There own brand helmets are good too, £30 ish for a perfectly good commuter lid is cracking value.
Bar that, just have a wander and see what you can see, they’ve often got deals on in store that are not on the website. My view is that their own brand stuff is, with the odd exception, very, very good for the money, be that their B’Twin cycling stuff, the Quechua hiking gear or the Kalenji running gear. I can’t be trusted to visit very often as I tend to spend far too much when I do.