for 'quick' cartridridge swapping,

There are some people who maintain that the head shell connections used can be problematic, and may over time suffer from corrosion or poor contact.

Furthermore, individual cartridges may require slightly different setup, especially if they weigh much more/less, which is hard to accomplish with headshells but easy with wands (which retain their unique setup with respect to balance, etc.) For these reasons, wands are somewhat preferred.

HTH

IMHO, VPI's JMW arms are the easiest to swap because all the adjustments are done on each individual wand. It takes about 15 sec to swap.

While you can set up the alignment in an interchangeable headshell and be done, you will still need to adjust for VTF and VTA whenever you swap (unless the second cartridge is a physical match) so it will take longer.

With an arm tube such as VPI, the counterweight is attached so once set, all that is needed to make a swap could be to reset VTA. Conveniently VPI provides a calibrated dial to do so. As Sidssp said, it only takes seconds to swap once all initial setups are dialed in.

But there is another advantage in using an arm with interchangeable headshells. You may be interested in reading some of Raul's posts on the importance of cartridge matching. This goes beyond the standard compliance/mass range that is often discussed. Raul discovered he could optimize performance of a given cartridge by experimenting with headshell rigidity and material type (resonance?), as well as weight with different model headshells.

So if you are interested in trying a few cartridges that are reported to work well in a VPI (or any other interchangeable wand arm that includes the counterweight), I would recommend that for ease and speed. But if you want to be able to optimize your arm/table to the greatest number of cartridge choices, you may want to go with a removable headshell arm.

05-29-08: Pryso
There is another advantage in using an arm with interchangeable headshells. ... Raul discovered he could optimize performance of a given cartridge by experimenting with headshell rigidity and material type (resonance?), as well as weight with different model headshells.

That's right--the currently available selection of headshells enables you to experiment with rigidity, characteristic resonance, effective mass (they vary in weight), and the various mechanical impedances and resonant frequencies you encounter based on materials used.

The standard Technics HS is pretty light at 7.5g but could use better headshell leads. The Sumiko is heavier at about 12g but more rigid and has better headshell leads. You can also get headshells of various woods such as ebony, cherry, and boxwood. What happens when you put an ebony-bodied cartridge on an ebony headshell?

Then there are the headshells from Audio-Technica--their proprietary "Technihard" alloy in 11, 12, and 13g weights and also magnesium at 11g.

And Needle Doctor now offers Ortofon headshells. I don't know what thos weigh, but they look good.

As for rigidity, the Sumiko uses two alignment pins instead of one. It makes for a very rigid joint.

thanks all for your suggestions! Each approach has it's merits. I'm wondering which arms feature the removable wands besides the VPI and Moerch? The Moerchs appear a bit more estoric than the VPI arms, and don't know how well they do on suspension tables like mine.
Another consideration (constraint) is the arm mounting pattern. Currently I have an Audioquest PT6 which I believe has the same mounting pattern as the Linn arms. Since the table is an AR ES-1, I would possibily have to source a new armboard (I've already emailed Sound of Wood but got no response!).

What does happen to an ebony body mounted to an ebony headshell?

I have had an ebony body on a Denon 103r and 103sa and would never go back to the factory body. I'm curious if anyone has heard an ebony body on an ebony headshell?