Yes you'd definitely be closer to Wythenshawe, and although St Mary's isn't much further distance wise, the traffic up towards town can get quite bad so you'd have to factor that in iykwim?
The rooms on MLU at Wythenshawe are lovely, as maternity staff we got a sneak peek at them before they opened up and they're very homely, i almost changed my mind actually and wanted to book there instead of St Mary's but for us it was about practicality as even though i work at Wythenshawe, we're literally just around the corner from St Mary's and my partner doesn't drive so we had to think about the logistics.
They're both quite similar in many ways to be honest- St Mary's is a new building (opened in summer 2009) so the facilities are very shiny, new and modern (although like anywhere in the nhs- that doesn't mean there's necessarily enough staff to actually look after everyone

) Wythenshawe maternity unit is a very old building but we're being refurbished inside, so delivery suite and MLU and the postnatal ward have all been done up very recently, and building work is still going on on the neonatal unit.
If you have any complications in your pregnancy or birth St Mary's is a good place to be as they have all kinds of specialists there, like fetal medicine, and their neonatal unit is massive and they do neonatal surgery etc, but if you're unlikely to need any of that and are having a straightforward pregnancy and hoping for a nice natural birth i'd say probably Wythenshawe was your best bet.
It's really hard to say though as i did feel i was well cared for at St Mary's, it was clean and new and the staff were lovely. It was busy and short staffed on the postnatal ward but that's the same anywhere i think.
Both the units are the same in the sense that you turn up in labour and are 'assessed' as being suitable for the MLU or sent to Delivery Suite iykwim?
The community MWs you'd see in Sale would probably be part of the Wythenshawe team, if that makes a difference to you.
HTH?
