I'd be happy if they fixed Mail's connection to Exchange (drops randomly - a know issue), or the terribly slow SMB - mounting Windows drives is just a nightmare. There is a fix, more like a hack really, forcing the OS to use an earlier version of SMB.
Are you talking about Mavericks? I'm still on Mountain Lion and Windows drives take a little while, but I wouldn't call it a nightmare. I guess what I'm asking is: did SMB get worse on Mavericks?
Yes, Mavericks started using SMB2 which has many reported performance issues [0]. Most people experiencing it can work around this by using cifs:// instead of smb:// or disabling SMB2 and reverting to using SMB1 [1].
Fix those two and I'm there.