I have just been listening to the P3+ driving my MS1's- a very enjoyable and involving sound. Not being analytical about it, as for me it is the enjoyment i find listening to well driven music that is the my main interest these days. All i can say is, Teddy Pendergrass sounds supremely funky to the max through this combination. The MS1's are still great entry level 'phones and and P3+ does a marvellous job of making them sing.
But, i am also a big RSA fan, and would love to listen to the P-51 and the new Shadow. I still miss my Tomahawk, but the P3+ does it's job well enough to make it a pointless task in buying a new one (then again, when it comes to the Tom's incredible battery life i may just have to go and hunt a replacement down).