I have wondered about the insert system. Both my machines are table top. And I too, get a sore back/neck so I've learned to take frequent breaks. However, I am tall and I find I need to slump/crouch to clearly see the needle+ particularly when I FMQ. A lower chair makes it awkward for my arms. I can't but think an insert would make the whole situation worse?

This is one I've been looking at instead of trying to make one. Also I have the adjustable Sewing Mates insert. It adjust for whatever machine you use. I love it. Check it out here sewperfecttable.com
http://sewperfecttables.com/sewing-table-original.shtml

I use my machine on table top. Not really the best but it works.

I have a Juki and took a 6' ft banquet table and cut a hole for the machine. I made a "platform" under the hole and it works great.

I bought a sewing table with a custom insert and my machine sits level with it....in front of that I bought 2 tables at Home Depot ( the kind you set up for a party) and put one in front of the machine table and one to the left of the machine in a L shape and it works perfectly while quilting and cutting out fabric.

For under $150, including shipping, you can get a Gidget table for a regular size machine, that will allow the machine to recess, or be on top. You can buy a SewSteady insert to fit any machine for about $69-$65. If you have a larger machine you can get a Gidget II for about $250, and I think that includes the insert.

The tables are 42"x19" and quite sturdy. I have to butt them up to a larger table to quilt, but they are fine for piecing.

I have a very old cabinet my husband took out the old machine made the opening large enough to put my machine in he also installed a lift it is really nice I don't remember how much the lift was but I am thinking around $100.

He also made the insert to match the cabinet.

I would love to have a desk with the machine on the level with the top of the desk. I use an extension on my machine but that isn't the same thing. Still have to lift arms up to stitch and it isn't even with the top of the desk so the quilt hangs over the sides.

I have a quilting table with a insert that is removed for when you need it. Very nice.

I bought a computer desk which is kind of straight C shaped /-----\. On sale at Staples for about $100. The middle section has a drop down area for your keyboard. I put my machine on that section for most general sewing, but can raise it up to the height of the rest of the cabinet if I want to use the free arm feature. Make sure you measure your machine's footprint if you go this route. Many newer machines are quite large and won't fit the smaller openings.