Actually, you can get the
250Q Select Plus for $312 at Amazon. If you mean the
Top Plus, you can get that for $299 from Amazon, but it's from one of their vendors called Hardware Sales Inc. In all my checking it seems to be a new Top Plus they are selling and not refurbished, but I was too chicken to order it, being that it's $100 cheaper than almost everyone else.
I do believe the Fein MultiMaster is probably still the best oscillating tool out there, but you are paying a hefty price to own one.
Porter Cable just came out with their oscillating tool which also has the tooless blade change system. You can see the Porter Cable in person at Lowe's stores, but it's cheaper to by from
Amazon ($115 vs. $134). Amazon was selling it for just $109 last week, but they tend to raise their prices a bit when at items starts selling real well.
With the assortment of blades and sanding pieces that comes with the Porter Cable I couldn't justify not buying it for $109. I have only used the tool to cut some studs and some drywall, but it was a pleasure to use. I would have been very frustrated getting out a little allen wrench each time I wanted to rotate the cutting blade to a new position. I can tell already that my RotoZip is going to see a lot less use now.
Edit: I forgot to comment about you wanting to primarily use the oscillating tool to sand with. In all the research I did last week on oscillating tools, before I decided on the Porter Cable, the only real negative comments I came across about the Fein were related to sanding. It seems that some of their sanding attachments use a hook and loop system which is glued to the attachment. When people are sanding they are heating up the attachment to the point that the glue is failing or something like that. Check out all the reviews on Amazon. Be sure to read the reviews for each of the MM models, not just the one you are interested in, because they all use the same sanding attachments (to my knowledge). One reviewer said that when they complained to Fein that Fein told them the manual states not to use the tool above speed 2 when sanding. I guess that is a pretty easy thing to miss or forget to do, so people are melting their attachments because they are running them at normal speed.