I think anyone would be surprised how good it sounds with a good source.

The bravo v2 actually sounds pretty good

Get an ASUS Sound Card I got one with nice headphones for gaming (HD595) and everything else and it's amazing you wont regret it. You'd be amazed on how good they are seriously equal to amps and DACs costing 10x-20x the price!  Everyone that has heard it says it blows away creative 

If you have a high end Computer then get a nice sound card "Not Creative"!!!! You will not regret it.  I got the ASUS Xonar Xense with a built in headphone amp that is very powerful Crystal clear sound and has an EQ plus nice software.  Its Very similar to the Essence STX if you want the PC350's...

The Fiio E5 its 20$ on Amazon it works like a charm for the price and its small.  Get the L3 Line Out for the Ipod it sounds much better than with out it. I can't find any for the price that match it.  

I guess some people are finally realizing the power of the TI TPA6120A2 Amplifier chip!  Its funny I was reading some posts on here that a lot of people thought that it didn't have enough power to handle higher end headphones.  That TI tpa6120a2 has it in spades with plenty of power to spare! ...

I believe the BB PCM 1792 and 1796 is better but I could be wrong both Bur Browns are Highly praised.  To answer your other question yes the ASUS Essence STX is that good and so is the Xonar Xense very similar card but different feature set.