I've encountered licenses that won't allow themselves to be transfered to other dongles. Apparently it's a feature.
Quite honesty I've found that the VSL/Syncrosoft system works absolutely fine on a consistent basis (long first scan issues notwithstanding). But that hasn't at all been my experience with every Syncrosoft-protected program. I have a couple of Steinberg or Steinberg OEM programs that either run intermittently or that simply refuse to run on my G5. Cubase 3 will not work. Period. The Scarbee Rhodes and Imperial Drums both work fine on one of my Windows machines, but only about 50% of the time on my main G5 - with the same dongle. I've been over this with Syncrosoft at great length; the fellow I corresponded with is very nice and helpful, but we weren't able to get this working properly.
And most Syncrosoft-protected instruments will crash the host violently if the dongle isn't attached and you try to insert them.
Being a journalist I try to tread carefully where peoples' livelihoods are concerned, so I'll leave it at this: there's still a lot of work that needs to be done to make this situation tenable. I happen to know of a developer who was forced to return a couple of customers' purchases because of dongle issues. That's just nuts.
Off the top of my head, VSL is probably the most expensive piece of music software on the planet - with good reason - so waiting a couple of minutes to launch it isn't unreasonable; clearly, they need to protect their investment. But that isn't the case with a $300 library.
Edit: to be clear, I have something like nine Syncrosoft dongles (yeah, I need to consolidate), and most of the programs work fine. It's the ones that don't work that cause the shouting, of course.