Ok, reason I asked is because underseat steering can be tougher for newbies to learn.
Test ride the Vison and see how you like it. If there's no shipping involved and the bike is in nice condition, $600 is a good deal. You can always resell and recoup all or most of the purchase price. Replacement Vision parts should only be a problem if there are tears in the seat fabric, seat frame damage, or if the bike had underseat steering.
You know the Actionbent comes as a kit, right? An experienced cyclist can figure it out without much trouble. The Actionbent works fine as is, but you'll get more out it with $100 in upgrades. $75 for the fiberglass seat, which is lighter and more durable, and about $30 for the open-cell foam pad (the stock fiberglass seat pad is too firm).
BTW, for $350 plus shipping, you can get a Tsunami 2 recumbent from Chuck's Bicycle Closeouts. It's basically a Jet Stream with different parts.
http://www.chucksbikes.com/store/indexcb014b.htm