Avalons are great, very common in the Ubran world, Beyonce, Jay Z, Rick Ross all tracked or still do on a 737. I love mine, sold the 610 i had, didn't like it on aggressive hip hop vocals or rnb/pop stuff, just wasn't for me (could of been my mic at the time also).
The compressor on the Avalon is discrete and does it's job (unless it's an older model which is pretty slow on the attack), if you are looking for color from the compressor on the 737, look elsewhere, it's a very clean sound just like the pre.
It's very crisp and clean or you can get a warm sound, whoever says you can't doesn't know how to work with an Avalon, it's capable of putting out thousands of different tones you just have to play with them.
With that said, there is a bunch of options now, do you want tubes? solidstate? ect ect ect.. You can pick up used Avalons all the time, i wouldn't pay for one new as id be looking at something else for that price but used? Yeah no brainer, $1,200 to $1,500? SOLD!