Any metal or wood and it easily pops its internal CB....other then that its good for very light stuff...sheet rock, foam....
I have cut through pressure treated 4x4 posts, flashing, old oak framing with my 12v (I think all of these were the cman) and PVC with both. You could just look at the blade and if you can see the teeth instead of a blur, you're pushing too hard. I just let the tool do the work.
The brands I mentioned, Bosch, Cman, Milwaukee, Fein all use the same kind of blades. Both HF corded, the cordless, & the air powered one (I have one of those too, forgot to mention) use the same blades. Imperial & Bosch are pricy but I find them more cost effective than Fein, but you can get as low quality as HF blades to do several cuts and when you look at cost per cut, Bosch or HF is what I usually get the best use out of.
The Fein is the heaviest of the ones I own, the air powered probably very close to the 12v tied for the lightest. I find this doesn't make much of a difference for cutting, can be a little awkward for scraping, and actually helps a LOT for sanding. I like to set my blade sticking out the side so it's easier to hold the tool as a handle like you would a football in 'half tuck' so it rests on your forearm/wrist area. It's awkward at first and it doesn't work for every angle but once I got used to it, the Fein is so much easier to use.