I have the less expensive Harbor Freight Multifunction tool. (The patent is up on the Fein Multimaster, so there are
much cheaper versions out by other companies, now.)
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=67256&xcamp=google&utm_source=googlebase&utm_medium=cpc&zmam=33951326&zmas=12&zmac=112&zmap=67256
I'm pretty handy with a screwdriver, drill or hammer, but major power tools scare me. Especially power saws that can cut off a finger or leg.

There are so many projects I have wanted to do myself but the jigsaw I tried to use to cut down some shelves just vibrated too much. Not only was it scary to use, it vibrated too much while cutting wood, for me to cut a clean, straight line.
Finally, I bought the generic version of the tool.

I've been watching the infomercial over & over, also various
Youtube videos. It uses the same kind of saw that cuts off plaster casts after one has broken an arm or leg. So it's
designed not to cut through skin & bones. It's also not supposed to vibrate like crazy while cutting.
Well, if it really does what it says it claims, and I can save so much money instead of hiring a carpenter to just cut 6" off some shelves and other projects, it's worth the price. But, doing a Google search, I found the cheaper versions came out, as Fein's patent for their $400 original version ran out.
Dremel now makes a $100
Multi-Max version and I bought the $35 version from
Harbor Freight just called the
"Multifunction Tool."
I did some test cuts on a scrap piece of wood and couldn't believe how straight & easy a cut I was able to do, with no vibrations. And I'm a female. I am seriously loving this tool.

I cut the shelves I wanted down and then drilled & assembled them and put the shortened bookcase
finally where I have been dreaming of putting the unit. It needed to be an exact size to fit a small cubby area.
Here are the shelves I cut down. The tall shelf was the size uncut. The middle size was after cutting. (It's leaning against the tall board so it only seems shorter than the pencil cut line you can see on the tall board. But, it is cut exactly to size, by hand holding the tool.) Look how straight the line is. The little piece was the cutoff piece, and it's not all chewed up at the bottom.
Now, I've been seriously rethinking some renovations I have wanted to do. Originally, I had to come up with workarounds that wouldn't quite do, because they would involve too much sawing to get custom pieces to fit. Now I can do them!
Youtube: Multimaster demo