Allen,
I'm still learning this "new frontier" myself, but I have spent a lot of time researching these spindles as well. Of course there are the VFD driven spindles like Patrick got
http://forums.azbilliards.com/showthread.php?t=268791
I don't have 220V in my shop, so I have this link saved away:
http://www.ebay.com/itm/281140469990?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
But for my first pass on my inlay/engraving, I'm going with this one:
http://www.ebay.com/itm/271335200268?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2648
I may eventually go with the VFD model with a water cooled spindle for a more permanent solution, but for the learning curve I am on, I've opted for the 400W model because of the increased torque over the 300W.
The model that you have bookmarked has a couple of drawbacks in my view. One, you still have to supply a 48VDC power source, not a big deal, but not sure if you realized that or not. Second, the torque on it is only 230 mN.m. The one I'm going with is "rated" at 500 mN.m. In my other CNC inlay thread, someone asked me if I was going to taper with my new rig. So, if I decide to taper with it, I'll want to be able to drive a bigger router bit, hence more torque will be required.
Finally, there is another 400W model where the speed controller is also a 110VAC to 48VDC converter, but it is only rated at 350 mN.m. This would be a cleaner wiring solution, but as noted, less torque for only a little less money.
Keep in mind that
none of the above reasoning is based on experience with my particular new machine, but I do have some experience with 2D CNC and tapering, so it is not completely blind reasoning, either.
I will be interested to follow what you end up choosing and how it works out for you.
HTH
Gary