For the price this is an outstanding HU, it has the functions you need for moderate use with amped up speakers and sub and doesn't have the bells and whistles you don't need unless extremely into your car audio which lets face you wouldn't be an Amazon for your HU or reading this!
For a unit that plays CD's it is better then the more expensive media player units only as it has 3 pre outs at better voltages, the screen display is ok although Id prefer to see song and artist names in one hit that one line at a time but wasn't willing to pay another £100 for that privilege. The connectivity to a iPod is good and full control is easy, slightly awkward and slower than using a iPod itself but not as bad as older models. You may struggle to get the connectivity lead 422i so check you can get this before wanting to do the entire install at the same time. Being able to use USB Flash drives is good too as you can have data, photos and music and it will simply filter the music out for you.
I had a Sony CDX-M8800 prior to this (flex cable broke repair didn't work!) which I thought made my car speakers sound better than they could be, this yet again makes standard BMW speakers sound very good for what they are, so to summarize a great sounding head unit that will make the most or mediocre speakers. Can't speak highly enough for this as it's an hoest bit of kit that isn't going to cost you the earth.