I've just spent all day playing Defiance. Popped for the digital deluxe edition yesterday when it was on super-steam-sale, spent all day yesterday downloading it, and doubled-down today with the season pass which, as yet, has no fruit to yield.
It's kind of hard to put into words exactly what it is. It's not quite an MMORPG, but it's not quite just a shitload of people shooting things at once. One thing it does... interestingly is that the loot treadmill isn't what you'd expect. A white-quality version of the same weapon you can find as gold or purple in the end-game has the exact same damage stat. The shields are the same way, too. You make your increased badassery through other means, but it feels to me like two noobs with white gear are worth more than one high-end badass with all the trimmings.
One thing that does annoy the living hell out of me, though, is that advanced alien energy weapons are worth crap compared to just shooting a fellow full of bullets. Borderlands does this too, and it pisses me off. Finding a gun that shoots freaking blue blaster bolts should be a hell yeah moment. I tried to love them, I really did, but lower damage-per-shot combined with blazing-fast fire speed and poor recoil control means you have to get up in someone's grille to actually deliver the weapon's DPS. And being up in the grille of someone against whom your DPS actually matters is a bad idea, because they almost all have monumentally more HP than you do, so you're really going to want to play a longer-ranged firefight with them. Plus, it also means you're going to burn through your ammo - you'll enjoy higher burst damage output right up until the moment your gun clicks empty and you have no more bullets. Then the other guy injects you with pain and you suffer.
Another thing worth noting is that, while the show and the game do tie-in storywise, they don't... Really seem to be inhabiting the same universe. Some of it could be explained as the geopolitical and economic differences between the places you go in the game and the city of Defiance, formerly St. Louis, Missouri; it comes up in the show that computers are fairly rare thing, to the point that the local mining magnate's record-keeping is all paper-in-boxes. Yet the world has computers aplenty in the defiance game, but that can be explained.
What can't really be explained away is how votan blasters are clearly superior to human weapons in the show, and the only reason you'd choose a human gun over a votan blaster is because you don't have the means to replenish its power supply... However, as I previously mentioned, you're probably not going to want to use any votan guns if you play the game. (Oh, and that really cool energy knife/dagger/short sword that Datak Tarr uses? You don't get one. Your melee is standard rifle-butt-smashing and pistol-whipping. Still does frankly amazing amounts of damage, though.)
One thing I should mention are Arkfall Codes. If you register for the game, it will mail you two or three automatically. Basically, they're six-character alphanumeric strings you enter into a website, and they're supposed to be things you can find all over, if you pay attention to things like the in-game art (such as finding them substituted for the last digits in telephone numbers on pizza adverts and such,) or to related tie-in material like the developers weblogs and such.
However, because of this, these codes are not unique; and they are not part of the advancement system, either. Therefor, it should come as absolutely no surprise to anyone that the internet provides. You can just sit there and manually enter all 166 so-far confirmed codes int the web-page to reap the benefits thereof, which include, but are not limited to, +1 to a number of nice weapon skills, +6 inventory slots (trust me, you'll want those,) an assault rifle and shotgun you're going to want to have (I just finished spending roundabout a shitload of ark salvage modding both of mine to have four mod slots each,) an ATV from the get-go (not that it matters a whole lot, you get a better one very soon after you get the first one anyway, but it may save you some time,) an EGO perk which is very helpful, I find (+45% ammo drop from enemies at max level; keep your hungry guns fed all day!,) a lock-box, and a couple of titles you may or may not care about.