All's been said already. I must say i like the mastered versions better 'cause of the wider and brighter sound. There are two opinions on mastering yourself:

One says that mastering is just a final technical step in the production. No mambo-jambo that needs a specific ME, just set the levels right and add some maximizers, stereo-optimizers and off you go.

The other say: Mastering your own work is like taking your own sister to the prom...

As for me, well... I think that in a lot of cases (no budget, not intended to sell professionally) mastering can very well be done by the recording engineer. My home-recording stuff and the demo's I make are all mastered by myself, using Cubase 5. For the two singles that I'm currently working on I have hired a pro-studio with engineer, real musicians and the mastering will be done by a professional ME...

Mike
www.mikewever.nl