James..... go for it
I moved here over 10 yrs ago and you would be very hard pressed to find anywhere within Stockport/close to Manchester that still retains a friendly "community" feel......it has got nearly all the shops you could possibly want ( i find the Co-op is fine for me although they do run out of some things if you are going in after work ie 5pm or later)......anything you cannot get locally get the train into Manchester or bus into Stockport,not that big of a deal.......or drive to Morrisons in Bredbury,Sainsburys Hazel Grove.
Train links to Manchester are great although as others have mentioned the trains are packed out at peak times but that goes for any peak time commuter train (we do seem to have the oldest trains on the network but thats another story.at least they do run !!)
If you are getting the train from Marple every day try and get a property close to the station.....the drag walking up the hill can be a killer esp end of a long working day (mind you that depends how young/fit you are
)..........the car parks fill up as well workdays approx by 8-8.15am.
downside to living in Marple (as others have said) is rush hour traffic going down to the direction of Stockport,very unpredictable ( except during School Holidays when its much better)....can be very frustrating being stuck for 20 mins or longer just to get to the bottom of Dan Bank ( you have to leave massively earlier than you would for a straight run to be on the safe side you get anywhere on time)If it snows you do not know if you are going to be able to get out of Marple,let alone taking a risk driving down Dan bank........if you do not have to drive into/out of Stockport rush hour then i can't think of any downsides to Marple worth mentioning.
Good Luck with your search