Beam is so much more focused. Also warmer and better CRI if you don't lose phosphor. I think the uneven surface creates some blurriness in the beam, but I can only notice on lower modes on a white wall.
There are a couple wall shots here. I have various build threads with beam shots. I guess I will toot my own horn and say that I believe I was the first person to post a "successful" dedome (Defiant Spotlight).
Others have tried gasoline with mixed results. Seems to remove the phosphor. I think Ohaya did a gasoline dedome.
The emitter in the center was dedomed using an acetone bath (Post link with below image). Totally removed the phosphor
Here's an asphric beam shot. Here is a couple beam shots from my last dedomed MT-G2:
