I currently have 2 clear-top 4 piece grinders, one with my living room setup and the other in my office. One's a sharpstone with the external handle for grinding. It also screws down rather than being magnetic. The other one's a weedstar which is basically a knockoff of the magnetic lid sharpstone without the handle. At first, I didn't like the handle, but now I actually prefer it because it grinds so much faster and tends to have less stuck in the chamber after I'm done my initial grind.
I love the clear-top grinders cause you can see what's going on without having to open it up, I usually will tap the grinder a bit on the table or whatever until I can't see much from the top anymore. In either case, these are probably my two favorite grinders at the moment, It's a toss-up as I like both styles, with slight edge to handle for speed, but edge to the standard magnetic lid style for durability, I always swear that handles going to break off, but I've had it for a while now and it's still going strong.
i had a small 4pc spacecase but i gave it to my sister, she used to have a 5pc that actually had 2 separate kif sections, one finer than the other, but it got stolen. That was pretty cool though. I have a weird grinder that's basically a 3pc that a friend gave me when I was grinder-less for a few months. It's got a separate kif section, but no separate chamber for the grindings. I don't really like that style much at all. I like to have a clear area without the grinder blades so I can just shove one of my tubes into it to fill it up. I also had a wooden grinder with metal grinding pins shoved into it. I never really liked that either, it was just slow and didn't really grind that well.