People rag on them, but I have an Invisishield and love it. (avoid the smudge free one) I have been using plain glass on my Evo for the past few weeks, the shield on the 3vo - it's not bubbly, rough or distorted.
But you can feel a difference, right?
I used to swear by invisishields, too. There's one still on my iPod. Used to have one on the DX. I got a screen protector from the VZW store. They were horrible. They didn't cover the bezel at all. They were cloudy and they felt like crap. Then I went to the nearest best buy, got one of those shields, and put it on the phone. It was such a drastic improvement that I thought that it was perfect.
Then I got the 3vo. I was waiting for a package that day, so I went to the Sprint store, got my phone, and went straight home without a screen protector. I marveled at how silky smooth the glass felt. I thought it was a drastic improvement over my DX in that regard. Then I got an invisishield. In comparison, it felt sticky/tough to move my finger over the screen. I think that thing was on for a few days before I peeled it off. I peeled the one off my DX, too, to see if it was the same way. Sure enough, silky smooth without the protector.
Since then, I've been looking for a good screen protector that can replicate that smoothness without compromising the clarity. I tried PhantomSkinz. It was better than invisishield, IMO. But it wasn't that much better. Definitely a bit cheaper. Then I got one of these Steinhiel protectors. I probably butchered the spelling. But I got an ultraclear and it feels almost exactly like the bare glass. I compared by gliding my finger over the 3vo with the Steinhiel then the bare DX. Barely a difference.
Are invisishields bad protectors? No. Their biggest advantage is that you can get one now and they fare better than the really cheap ones. But I would never get another one. After feeling how smooth the screens can be without a protector, any protector that doesn't feel close to that is no good. For NextPhone, I'll get a cheap one that is crappy, or go bare, until a Steinhiel is made and delivered.