I've grown up with Eminem's music since I was 9, and been a genuine fan since The Eminem Show. The previous albums haven't been his best; Encore was flawed, a number of brilliant songs in between tunes which seemed more an imitation of Slim Shady rather than the real Slim Shady. Relapse I enjoyed, but I can understand why it wasn't popular.
Recovery is a change in Eminem's style. If anything, it conforms to many current hip-hop and pop styles. Simple examples are the use of Pink and Rihanna in songs, where before Dina Rae (a relative unknown outside of rap) featured. Beats are faster, there are genuine hints of love ballads (instead of murder ballads), and it just seems like Eminem's accepted he's changed rap forever, but he can't change it any more. This may not be a bad thing. Slim Shady/Eminem/Marshall Mathers are each different entities, so leaving Slim Shady to rest, with the brilliant work he did may be the best way for Slim to quit as the dominant entity.
As for individual songs on Recovery, Not Afraid is brilliant, while So Bad is a classic (the fact it's produced by Dr Dre may not be a coincidence). Going Through Changes is probably my favourite, for the moment. W.T.P. is a weak song, and I wish someone else sang the chorus to You're Never Over, while the absence of D12 (even without Proof) or Dre is disappointing. It can be difficult to get into as you compare Recovery with Eminem's old work, but once you're past that, you can recognise the album's brilliance.
Inevitably, Eminem has grown up throughout his career. From rebellious lunatic, to annoyed genius, to concerned parent and American to grieving friend, most with healthy doses of humour included. We've grown up with him. Recovery is a veteran rapper masterfully plying his trade, and another evolution of Eminem for us to experience.