Re: I had the same experience with 123-reg.
I've used http://gkg.net/ for about 20 years with no issue, but I must admit I haven't checked them for value for money lately.
When I got uk domains (gkg.net didn't do them), I just went for the cheapest I could find (I too only use the registration services, so the quality of their support/hardware is irrelevent to me) - I went with http://www.crazydomains.co.uk/ which were the cheapest at the time (about 4 or 5 years ago). I've had no issues with them, and even had prompt and knowledgable support when I had a query. I don't think they support DNSSEC for some stupid reason, so that may be a dealbreaker.
As for the cost of moving, you basically pay for at least one new year with the new registrar for the domain, and this time is added onto the time the domain already has to live, so ultimately, it doesn't cost anything to move.
By the way, I wasn't one of the miserable sods who downvoted you!