Since you asked... I'd say keep your Dewalt kit and if you really need
a cheap RO sander, get a Ryobi at the orange borg for $35. If you
don't, keep the nicer router.
I have the 618, and like it very much, but the variable speed isn't
what I like best - the overall quality and solid-ness is. It is also
versatile - fits PC sub-bases etc. VS and soft start are convenient,
and can reduce burning sometimes. Unless you're doing raised panels or
other very large bits, VS isn't really necessary. If you want it,
though, and you might return the 616 anyway, look into the dewalt 618
kit - only a little over $200 (try Amazon, Google, maybe Amazon
reconditioned, or toolsdirect.com says 110% price guarantee so see if
they'll beat Amazon...).
That's my advice.
Remember, though, that a piece of advice is like a butt - everyone has
one and most of them stink.
Andy