I don't believe it makes much of a difference, unless you are only going to apply to Flybe and BA! I was modular, used three different schools (one for distance ATPL, one for PPL / CPL / IR) and one for MCC) Of all the people I know who have recently got jobs, most have used several schools.
The market is changing, and nothing is certain, but it is mainly the schools themselves that would like you to believe you cannot go anywhere else - it's in their interests!
Search these forums - there's loads of useful advice (and a load of crap advice) but you'll soon sift through it, and find out what you need to know.
Good luck - and don't be afraid to change schools.
(BTW Cabairs Alsim is good, but for not much more you could easily be in a full flight Airbus / Boeing sim, learning the basics as well as doing your MCC)
DW.