I have a small area I want to cut out which is like two ply metal. Is a metal cutter best or jigsaw. I will have to buy whichever one, so I thought I'd ask. Thanks Mike

3" thin carborundum blade. X on the Jig Saw

If its in an open area an mostly flat I'd use a jig saw with a metal blade. If its tight and uneven I'd use a 4-1/2" cut off wheel on a grinder. If you're cutting out an area and not starting on the edge you'll need the cut off wheel to cut through the metal so you can use the jig saw.

If you have the room to get in there, my first choice would be a rotary cutoff tool.
The pneumatic ones from HF work great and they come in different orientationsof the disk wrt the handle.
Only about $10 if you have compressor.

http://www.harborfreight.com/air-tools/spe...tool-69473.html

A small angle grinder with a razor blade grinding wheel does a nice job.

I've used a multi-tool. HF sells one and has lots of cutting wheels/saws.
It's a fast oscillating tool, so differs from a cut-off wheel pneumatic tool. But you can start in the middle and not at an edge.

http://www.eastwood.com/air-body-saw.html Easier to maneuver than a jigsaw.

A cutoff wheel makes some clean, straight cuts as well.