Agree with Tinam on the whole mastering debate - your music was certainly good enough to play to Freinds impress record labels Ramshackles - and if you got signed surley the record company would pay for it?
Agree you should present your music as best as possible but this is getting so micro anyalitic that it's impossible to tell the difference - particularly as its streamed over an Internet connection from a compressed MP3 - if not I am sure my point still makes sense.
To use an anology - We bought these really super duper PC's for my company - all singing all dancing - cost a bomb - but we are limited to then quality and strength of broadband we receive - which basically means we could have bought a PC world special (£299) and it would have performed the same.
As an aside the songs in your EP sond awesome RS - I hope you have badgered some marketing undergraduate to promote your band - seriously your music is good enough - its all marketing now 
Yes it's streamed over the internet, but it is a wav file (although I dont know if soundcloud converts them?)
Yes, it's subtle differences but I think they are noticeable over the net - but as I've said, mastering is not for everyone, certainly not if you have no intentions to....whatever - 'get your music out there' or whatever it is called...
But some of the reasons I've gone with mastering are not really to do with the difference between the mastered track vs mixed track:
Heres my reasons:
1. Start with the micro analytic stuff
It gives the bass frequencies a bit more punch and definition, and the whole thing has a bit more depth and is wide and open - IMO
2. The biggest-micro analytic (
) difference is when you hear the whole EP. My mixes were all different volumes, and the relative volume between different parts was all different. Doing whatever it is he does, clever Eq'ing, compression, whatever, the whole thing has a coherence it didnt have (again, IMO).
3. Of course, having listened this crap 1 billion times, it's probably easier for me to notice the difference!
4. The thought of my music going through all those expensive toys (heres one of them:
http://www.analoguetube.com/mainpage.html - check out the price in the lower right
)
But heres the 'bigger' reasons:
1. Get the master CD that can be used for replication and/or vinyl cutting.
1. Actually, based on conversations with the mastering engineer, my mixes underwent a few revisions before being handed over to him. I think this made a huuge difference.
2. A fairly big time engineer made time for us at the weekend to do it at a much lower price. I can't say no to that for a number of reasons. For one thing, its another person that will listen to it and who knows who he might play it to? Another thing is it's a chance to hear a big time engineers' take on things and it's a nice credit to put on the back cover
It's really this 'extra ear' that is the big help - having a pro go over everything.
But I agree, when listening for the differences between individual tracks, after taking the loudness away its more than micro analytic!
Unfortunately, I dont know a single marketing student...I dont even know where the business school is :S
