It can be very frustrating buying a scroll saw if you have never used one before. Something like buying a musical instrument. you have to take the word of the salesman for it unless you have someone with experience shopping with you.
You have done the right thing, coming to ask questios.
The saw is an entry level saw manufactured under several names.
Jet, Craftsman, Mastercraft, Ryobi and a few others.
The UK site
http://www.jettools.co.uk/benchtop.html offers a variety of bench tools I have not seen here in Canada.
Like Mike said one thing to look at is how the blade fits in the lower chuck and how hard it is to tighten.
Many saws made over the years were not designed by people who have to use them. I am sure we have all cursed one manufacturer or another.
I am not sure on Dianes version, the Mastercraft, whether or not the blade clamps are tool less. The one I saw at my CTC needed an allan key.
Before you buy the saw, make sure the salesman clamps a blade in it and even if you cant cut with the saw you should turn it on, set the tension and run it through the speed range. This will let you know how severe the vibration is.
There are ways of reducing vibration, like bolting down the saw to a bench or a sandbox. Or even making an isolating table that will fit over the exsisting one.
Most saws in this price range are built to a price. That being said some are very servicable. I still use a Delta 16: VS saw and cut out acceptable projects. I would buy myself a better saw if I were going into production but that has never been my intent.