I moved to house about 2 mins from a train station and it has been a life changer. You waste so much of your time commuting and you don't see it until you don't have to. Right now I can leave my house at 8:25 get the 8:34 comfortably and be at my desk for 8:50.
Buying in the city is higher risk on capital values - as WW said the market is driven by investment and when that stops it will be like a switch going off - a lot will depend on the supply at that time, if some big schemes are completing the market could die a death - if not then it could be ok as schemes in the pipeline just won't get built.
That said the higher end will be less impacted - investment yields do not work for premium apartments and they tend to go to owner occupiers - people with serious cash tend to buy them.
On balance - I would pick a couple of stations in nice areas: Marple - Heaton Chapel - Wimslow - Bramhall - Cheadle Hulme - etc. And buy something within a 5min walk. If you can find something cheap you could rent out afterwards then even better but you might need all of your cash, capital value will be solid though.