If you'll only be turning pens, bottle stoppers, boxes, and other spindle related items, whichever option you choose won't really make much difference. If you get into bowl turning, you will need to focus on how SLOW the lathe can go.
Almost all bowl turning is below 1000 RPM, pen turning will vary from 1000 - 3000 RPM. When bowl blanks are being roughed out (turned round for the 1st time from a block of wood) you will WANT to have a speed slower than 500 RPM for anything larger than a 10" diameter.
The real advantage of VS or handle adjusted speed over the belt is that you can quickly realize that you have started the lathe while it was set to spin too fast and make the adjustment on the fly rather than having to turn the lathe off and change the belt. Having a standard methodology of starting your lathe (check to make sure the block spins clear of the tool rest, verify the speed setting via eyeballing the belt or the vs dial, making sure you have eye protection, standing clear of the rotating block when starting, etc) will go a long way to addressing this safety issue even if you have a belt.
I've used belt driven Jet minis, handle adjusted Deltas, and a VS Powermatic. For bowl turning, I love the VS because I can slow my RPMs down so much. You can easily turn 10" bowls on a belt driven Jet which has a bottom speed of about 500 RPM. If you muscle up to bigger bowl blanks, then you will want to seriously look at the range of speed.
Most of the lower priced lathes (sub $600) have a low speed of 500 RPM which is fine for most things, because they also have a smaller swing. If you start going all Tim Taylor (arghhh, arghhh!) then you need to consider a larger lathe, and slower speeds over everything else for your safety if nothing else. Don't forget a face shield in your purchasing as they really are necessary whether you are turning bowls or pens. Its really hard to do a lot of things if you're blind or have super glued your eye shut!
May all your turnings be smooth,
Brodie