Yes, it works great, I highly reccommend it. There is no better adhesion modification you can do to your 3d printer if you are printing ABS, and I include building an enclosure in that list. According to my year long test and my thermal imaging camera, it works an insane amount better than stock. A 12" x 12" plate will be slightly too big for the stock bed corners on a Taz 5, here are clearanced ones: http://www.thingiverse.com/thing:1098784
You can also see the aluminum bed in there with a Buildtak sheet on it. PEI works well too.
The tricky part is finding a truly flat 3/16" thick metal sheet. Aluminum or copper work. I seem to be the only person who has attempted this that actually ended up with a truly flat plate direct from the plate maker. Ideally you would want a 3/16" thick 12" x 12" 7072 tool plate that has been machined to tolerance. Near as I can tell, such a plate doesn’t actually exist unless you have one custom made. A flat “mill finish” (just came off the rolling mill, rough) plate should work since you are adhering stuff to the top and bottom, but only if you get a flat one. they are easy to straighten I find, but some people find it to be a deal breaker.
You adhere a surface of some sort on top (i’ve never tried directly on the plate, that might also work), the bed heater to the bottom (Lulzbot or IT works https://itworks3d.com/product-category/parts/ have them in stock usually). If you go with an Aluminum plate, it’s also going to be slightly lighter than the stock glass plate which is an added bonus. A 1/4" thick toolplate sounds like a good alternative in theory, but they are much to heavy.