I've used a national "call centre" conveyancing solicitor for one purchase and a local solicitor for a later sale and purchase. Not much in it in terms of price but it was a lot easier dealing with the local solicitor - we were always dealing with the same person, they understood the locality and produced a better standard of search. It was also much easier dealing with a local firm for the surveys on the second purchase as well (I'd also used a national company the first time) - and more accurate, as things turned out.