Vintage Phono Stage? pros and cons

Depends on what price rangee your talkin' about.
In the $300 to $1000. range.. new is good, recent used of those is good.
For the big ticket, $2,000 and up retail, vintage is fine.
New designs are good, but the vintaage ones are pretty good too.
This is, of course just my opinion.
I own currently:
Bryston 1.5 new
Audio Research SP-15 preamp with phono.
Audio Research PH-2 balanced phono

Elizabeth has hit it on the head. I think if you like warm for the slant of your system, then vintage can/is better in general.

In fact, I love most of the vintage phono/preamps/recievers I have heard.

Musichead,
You are right. If you know your history, you can get a killer phono stage for not huge money. I find the best ones are embedded in top-notch preamps from the late 1970s. I have one I will be hooking up again tonight. It is a joy.
Vintage pres (with decent phono stages) I currently own:
Jadis JP-80 (euphonic)
Pioneer C-Z1 (ridiculously transparent, not "solid state-y")

A Phono Stage is the most critical unit in the whole chain. With no other unit you can win or loose so much. When it is done right, it is not a question of age.
Working on top level 1990 is still top level today (Science is knowledge ---> RIAA, precision, temperature, parts... ).
We have now a lot more units available, but only very, very few are outstanding. Nothing changed. Like a famous European Designer (Mies van der Rohe) once said: "God is in the Detail"