Having lived in both (Lancs 20 yrs; Surrey 10 yrs) I've probably a good idea but it does depends what you're looking for.
They've both got different strength and weaknesses and quite different sized communities. If you live in Guildford or Woking for example, then you'll find Preston much bigger (it's a city) and compared to virtually anywhere in Surrey Blackburn isn't going to impress.
If you want village life then (imo) Lancashire and it's countryside easily trumps Surrey (e.g. Barley, Longridge, around Forest of Bowland) and has lovely small towns - Clitheroe stands out, garstang too.
If working in Blackburn I'd suggest looking at Clitheroe, or possibly around Rossendale, Rawtenstall, Ramsbottom which give you the option of getting into Manchester too.
Lancashire generally does small towns/villages better than large towns - it's not like Yorkshire where you could be blown away by Harrogate or York.
Lancaster is a lovely city but I guess that's not close to your new work.
To counter the SE bias of the forums having spent 30 years across the two, I'd choose Lancs over Surry - oh and it's Prestonians ;)