I scored one pretty easily at an auction site, they aren't super rare.
It's a straight stitch machine, in a dark green crinkle finish. I love the deco styling of the badge and dials..
It takes regular 15 x 1 needles, the bobbins aren't at your fabric store, but are easy to get online as they fit many machines. Here is a link http://shop.sew-classic.com/Bobbins-White-Kenmore-Rotary-5-pack-744.htm and sometimes you can find them on eBay.
Some people don't like White Rotary machines because the threading is a bit different. It isn't hard to get used to, but it is a very different tension mechanism. SewUsa has a great diagram that makes it really clear. http://www.sewusa.com/Threading_Diagrams/Threading_Pages/White_Sewing_Machine_Threading/White_77_Threading_Diagram.htm
Another complaint is that it is a friction driven machine. Rather than a belt driving it, there is a rubber wheel which rests against the hand wheel and powers the machine.
If it does develop a flat spot, since it it an external part it isn't hard to fix, or replace. I have read about shaving it down until smooth, but since I can find a rubber pulley online at somewhere like Sew Classic for under $5 I would probably take that route.
My 77MG came with a tin of rotary attachments,
But even if you aren't so lucky, these are easy to find on eBay and other sites. There are different size of openings on the top clamping rotary attachments, this machine uses the ones with the 3/16" wide opening on the top.
So not a replacement for a featherweight. It does come in a similar case, but in the case the whole thing weighs about 30 lbs. But a sturdy straight stitcher, with some cool retro looks. I haven't made a project on this one yet, wonder what it wants to make?