I've spent about an hour or two in Hellgate over the past couple days...
I can see why people are not super impressed with Hellgate.
The first thing I noticed that was bad, was the tutorial. They overlay text on the screen across everything. If you've got your inventory open, its not exactly easy to read... also, its self advancing and not spoken, therefore if you miss it you're outta luck. Their normal dialog boxes would have been much better for tutorial text instead of this... plus, there's no way to skip when you create your game. I played through the demo before getting a retail copy, and I already knew what to do.
From this point on, I basically stopped caring about story. Its all text and kind of annoying so I've been running up to an NPC, clicking next as fast as I can, then clicking "accept" to get the quest they're offering. From this point on, it has been typical MMORPG style quests, "Go Kill X Dudes", "Go get me Item X", "Go visit this dude in this safe zone." Its easy enough to run through these to get your feel for the game, but I really hope these aren't all they are.
The inventory system isn't horrible, but its not great either. It feels like they were trying to be somewhat innovative, but fell short a bit. Its very easy to fill up on loot, so you'd better have the HG:L version of a Town Portal / Escapipe so you can run back and sell off stuff.
All these shortcomings aside, I do enjoy the atmosphere, the idea behind the game, and the way it plays. I'm a Blademaster, which means I run at people and hack them up. Its fun and mindless. I have yet to try the Multiplayer component of the title, but I'm guessing that is where most people spend their time.