I wouldn’t use a plain Gmail account because of the ‘on behalf of’ thing leffeboy mentions above. It just doesn’t look very professional.

Google Apps free was brilliant. I got mine when they allowed 50 users and set my mum up with one for her B&B only a few days before they stopped offering them. Now sadly irrelevant to the OP. I am very happy with my Google Apps account though, even though a free version it has been very reliable. I expect Google are using all info that comes through my mailbox for their nefarious (sic) purposes but I don’t care.

If I needed to set up a new domain now I think I would pay Google for the paid version of apps just because the free one has been so good.