The Grizzly 18/47 Lathe is a great prioce and a pretty good lathe. I almost bought one last year before deciding to go with a Jet 16/42 1.5hp.
I know after looking into the Grizzly lathe and talking to tech support from Grizzly, that the specs are incorrect. One place they say it can go down to zero RPM's and another place it says it can only go down to 100rpms. Most people don't care if it can go below 100rpms, but for sanding big bowls, it is great having a machine that can go down to at least 50 rpms like the Jet. Especially when you are using a drill with the round sanding attachments.
I also read on some post by a guy who had the Grizzly 18/47 lathe that when he got down to 103rpms or so that the motor would act up badly, jumpy, jittery, like it was stopping and going. I also read that if someone where to fix the problem so the Grizz could go down to 50 rpm's then their motor would burn up as the electronics in it are not as good as the Laguna.
Also from those who have the PM3520 lathe that has a 20" over the bed say they never need that much space as most people don't buy or want their massive vase's or bowls as they have no place to put them. The best selling vase's and bowls are in the 11-13" diameter range.
Just some food for thought and the reason I went with the Jet....Plus If I ever wanted to turn something HUGE, I can move the headstock to the end of the bed and get a floor stand and turn a bowl all the way to the floor~!
I do most of my turning at the end of the bed as I don't have to lean over (back problems) and can see what I am doing much better.
Good LUCK~!