If you are able to spend $500, save another 3 notes and buy a Sytek MPX-4Aii. You get 4 channels, of killer transparent preamp. 2 channel have Burr Brown op-amps for a more silky sound. This is a high end pre that compares favorably with the very best.
The units list for $1,680, but you can buy overstock units (brand new units) direct from Sytek on eBay for $803.65 shipped.
Here are some reviews by the rags. These reviews are for the cheaper units without the Burr Brown IC's that list for about $1,400.
Here are some reviews of the unit:
A review in Electronic Musician
http://www.sytek-audio-systems.com/review3.html
A review in EQ magazine:
http://www.sytek-audio-systems.com/review2.html
Electronic Musician Editor's Choice Award:
http://www.sytek-audio-systems.com/review1.html
Tube Dude made a post not long ago in the Microphone forum and he said: "think smart". This is an area where I think that advice is apropos. You can spend $500, or you can exercise a little patience, and save up 3 more Franklins. It would be comparable to spending 500 dollars on a unicycle, or saving up and spending 800 bucks on a Lamborghini. Sure the unicycle will transport you, but not as good as the Countach.

Plus, you will have something you will never need to upgrade. Sure you might buy other preamps, but this one will never become useless to you like some of the cheap preamps.
My $.02 worth. YMMV
Taylor