Nationwide flex plus, check out the benefits. It's not worth buying outside this...
It depends on the sort of cover you want.
For example, I would always prefer to be recovered to my chosen garage. But all these bundled breakdown services (that I have seen) only allow for a local recovery. My RBS, for example, is a 10 mile radius from the breakdown, so pretty useless if I'm in the next city, 20 miles away, when I break down.
I had this once on my P38. They couldn't fix it at the roadside, and so could only recover me 10 miles up the road. I didn't want some numpty who was completely clueless about these things to be looking at it, nor did I want it recovered to the nearest LR dealership either. Luckily it was only the EAS had tripped so it was on it's bumpstops, but I could, and did, drive it the 60+ miles to my preferred garage, minus the 10 miles the guy actually took me up the road (it was on his way home anyway thankfully).
So last year I went through quidco, and saved about £75 with the AA. They want £180 roughly to renew, but I wont be doing that.
Of course, if you're happy with just the basic recover to nearest garage, then the bundled breakdown service with Nationwide will do nicely. Plus the mobile phone insurance is decent too. And worldwide travel insurance is a bonus.