Curved and Straight Tonearms


Over the last 40 years I have owned 3 turntables. An entry level Dual from the '70's, a Denon DP-52F (which I still use in my office system) and a Rega P3-24 which I currently use in my main system. All of these turntables have had straight tonearms. I am planning on upgrading my Rega in the near future. Having started my research, I have noticed that some well reviewed turntables have curved 'arms. My question: What are the advantages/disadvantages of each, sonic or otherwise? Thanks for any input. 
ericsch
The last time I looked,most high end tables come with a straight arm. I don’t think it makes any difference,it’s all about the design of the arm. Take a look at this!
http://store.acousticsounds.com/index.cfm?get=results&start=1%20&CategoryID=111
I think the best way is to try the Audio Craft AC3000MC / AC4000MC with multiply armtubes of the different shapes. 
It looks like the OP is looking for a table that comes with an arm included. I doubt he is looking at a vintage separate arm!
S shaped arms allow for a greater pivot point distance than a straight arm - so less tracking error....
The pivot to stylus distance determines the degree of tracking error, and since the pivot to stylus distance is a straight line, different shapes of tonearms with the same pivot to stylus distance will trace the same arc.

The greatest advantage to a S or J shaped tonearm is it ability to be designed with a detachable headshell as the offset angle is built into the arm design
@yogiboy 
I doubt he is looking at a vintage separate arm!

I mean if someone would like to compare S vs. J on the same arm the Audio Craft and related stuff with removable artubes is a good option to understand which shape is the best for the owner. 

I have 2 "S" shaped tonearms and 4 "J" shaped tonearms and i can't say which one is better based just on the armtube design.