The first thing that really stood out about this piece of cookware when I bought it was the weight. It's heavy. Really heavy. But for a cast-iron skillet or pan, that's a good thing!
The instructions explained that unlike traditional cast-iron cookware it would not need to be seasoned, as it had a enamel coating which would "resist flavor absorption" - only a light coating of oil was supposed to be needed to prevent food from sticking to it.
The grill fit nicely over the burners of my gas stove. I tried using it the first time to grill up some small filet steaks that I'd been marinating for a few hours, along with some vegetable skewers. They did all come out very tasty, although I found that the steak did still want to stick to the grill, even after coating the pan with oil before using it.
In grilling up several different meals since then, from swordfish skewers to pork chops, I've found that the grill definitely has "hot" and "cooler" spots depending on where the stove burners are beneath it. Even with allowing the pan to warm up for 10-15 minutes or more before using, this seems to be the case. That's not necessarily a bad thing: for instance, when cooking thick pork chops I placed the bone in the hottest zone, so that the meat there would cook through thoroughly without overcooking or drying out the outer parts of the pork chop. But it's important to keep in mind when using the pan, and understanding how to try to take advantage of the heat properly.
You can definitely develop nice grill marks on your meat and vegetables using this pan, and the grilling flavor is quite comparable to using an outdoor gas grill. Do make sure to have your stove vent running, though, when using this pan - the night I made the steaks on the pan I really started to smoke up the house!
I've only used the griddle side of the pan once so far, to make pancakes. It worked well, although I'd note that the surface of the griddle side is a bit rough - I'm not sure how well it would work for, say, cooking eggs or something else more delicate. However I'm looking forward to using it the next time I'm making a Mexican-style dish and want to warm up my tortillas nicely.
Cleaning the Pan
Cleaning the pan, specifically the grill side, has been the biggest issue I have with this cookware so far. Even with oil coating it before use, meat tends to stick to it and if it burns on to the ridges, it can take a long time and a lot of work to get clean! I've found my best solution is to pour hot water over the pan immediately after use (before moving it off the stove), then clean the pan in the sink right after eating. If you leave the pan to sit overnight before cleaning it, or wait too long otherwise, it's just a mess.
Storage of this pan is also a bit of a hassle. I have a big kitchen, but even so finding room for this pan when not in use and when I may need all four burners on my stove is a bit of a nuisance. Fortunately I have a double-oven and it's rare I need both of them, so I tend to store the pan in the second oven. But for someone with a small kitchen I'm not sure how practical a large grill/griddle like this would be.
The more I use this pan, the more I love it. Yes, cleaning it is definitely the biggest hassle but I find I use it easily 2-3 times a week at this point - in fact I haven't even touched my outdoor grill once all summer as I prefer the results using this grill pan!