blinddrew wrote:What are you wanting to achieve with your compressor(s)?
Some nice transparent compression for tracking vocals & acoustic guitars mainly.
If you want transparent and you are recording digitally at 24 bit, there's no need at all... that's because If your gain range is anywhere near reasonable, you will be very far from the noise floor while simply not being able to overshot. Or vice-versa, if you are overshooting and feel you need a compressor, it means that your gain structure is wrong. A compressor set up to as transparent - slow attack, fast release, threshold set to grab only the loudest transients, will do literally nothing - it'll be like you were recording with a bit less bits but still in the sweet spot.
The only reason nowadays to use your compressor in input is to color the signal. I do it all the time with my LA 610 but just because I like what it does... and transparent, it's not.. because it's the point.
But you mentioned "analogue color"... then I'd suggest you focus on any kit with transformers inside, regardless of what it is (can certainly be a compressor, of course). That will not be transparent but give some additional character to the signal, especially not high end stuff (which tends to be expensively designed to be very linear in its behavior).
However, and apologies if I am wrong, I can't but suspect that the real answer to "what do you want to do" is "add something to my mixes that I feel it's missing".. in which case you have the right idea but the wrong solution. Outboard it ain't - unless you're prepared to go for a full good recording studio desk and multitrack in anger thru it. Everything else being equal (performance skills and recording space), you're probably better off experimenting with different microphones or look at your mixing chops.