The comparison is fraught with difficulties....
You can go out and pick up a bottom of the line 1970's TT for $300, and then find a TOTL 80's DD for $30.... so what do you compare and how do you compare it?
The used TT marketplace is highly fashion driven - lots of 70's "woodies" go for substantial amounts, where composite plinth 80's models of a superior lineage go for pennies... they don't look "vintage" enough.
And then there is the anti-Linear Tracker bigotry... also a matter of fashion really - with LT's from Sony, Technics, JVC, etc... which originally sold for $500 to $1000 (1982 dollars!) now lucky if they fetch $100 (2011 dollars).
Also the claims with regards to "arm quality" .... sure there were bottom end rough and ready units around then as there are now (anyone want to talk about the arm quality on an ATLP120?...

uke: see
http://www.audiocircle.com/index.php?topic=96782.0)
There are very few arm manufacturers now - which is why you see Jelco and Rega arms on so many different turntables (with tweaks and adjustments by individual manufacturers...).
But in the late 70's there were high levels of competition and huge volumes being manufactured.... the perfect environment to guarantee that the mid-market is high quality. (not even mentioning some of the legendary arms of the top end which are still very much sought after now!)
Like buying a car, the intrinsic value of the new item is less than 50% what you pay for it retail.... which is why it loses that amount of value as you walk (drive) out the store....
When purchasing used the formula is different... Intrinsic value x current fashion factor = market price
We are in the second "valve" period, and all things that "Look" vintage get extra fashion points. Anything designed to "look" modern or high tech loses fashion points.
If you want sound quality value today in the current market - look for early 80's turntables (preferably top of the midrange, or bottom of the top range) of the "high tech" appearance style, preferably linear trackers. - the perfect storm of anti-fashion features.
The end result should cost less than $100 and perform on a par or better than any currently available new TT under around $1000.
On the other hand I have seen a number of postings where the criteria were: good/reasonable sound, great looking vintage style with lots of wood.
And by coincidence here is Denons anniversary DP-A100 - for $2500 you get the exact same arm as is to be found on the ATLP240, and the Stanton ST150..... but you pay an extra $2000 for the shiny wood.... anyone want to discuss the impact of fashion on the market and market prices?
And then there is the issue of auditioning....
Hearing something in a showroom is almost meaningless.
Isolation/Vibration issues are related to the individual audiophiles home environment... and different turntables (all of equal high quality) will respond completely differently to it....
System synergy/matching can completely change the sound of a setup - and the store never has the same setup you do.
The room has a greater overall impact on the sound than anything else with the possible exception of the speakers (and possibly greater than the speakers) - yet an audition is always in a dealers showroom and NOT in your house....
It really comes down to if you want life to be easy - and you want to take something home that works first time.... go with a dealer.
If you want the best possible value for money, and are willing to invest the time and effort in research up front and TLC up back - go used/vintage.
bye for now
David