Re: I have a couple with them
I've used plenty of other firms, including CrazyDomains (HQ is in Australia, but service is OK), and HostGator. If you look at domcomp.com you can find a number of other registrars but
(a) watch out for "too good to be true" pricing (most of the firms mentioned are in USA and some do USA-only low prices, such as 1and1 - which launched its server farm business in N America with free hosting for 3 years but you had to have a US phone number to be eligible).... and
(b) one or two US firms want to charge a transfer fee, or a transfer fee and then renewal (if the renewal date is say more than 3 months in the future). I have a half dozen .uk domains at 123-Reg which will be moved before renewal becomes due in 2018.
I mention the comparison site as it may be of interest to those not wanting to be tied to .uk any more (!) The majority of the domains I manage are not .uk thank $deity.