tl:dr I like the game. I'm buying it.
I've followed this game since almost as far back as '03 first as lurker then as ngonzogo then Zuku. Didn't get the game (for sundry uninteresting reasons) until I downloaded the two week trial. After eleven or so days, this is my take.
The UI: I read a lot about how clunky and unintuitive the UI is. I don't play FPS so maybe I'm not a good judge but I don't think it's bad at all. It is highly customizable. My biggest issue is that I've had to learn to play right-handed b/c I'm not comfortable re-mapping the entire setup for left-handed play. I have not re-mapped a single key or button yet. I'm at the stage where I will want to start making changes, tho.
COMBAT (in general): Again, I'm not an FPS'er so take that into account. Gear matters. Player stat/skill levels matter. Twitch matters. Ping matters. I guess this falls into the category of: Duh.
This early on it's interesting to compare melee v. archery v. magic and see how different weapons work.
PVE: There is a ton of PVE content. The world is there. I've played with no plan. I've read no guide. I just logged on and started playing. There are a lot of newb quests to get a person started and geared and introduced to various aspects of the game.
PVP: Frankly, I expected to get ganked often. So far I've been ganked twice. I haven't seen anyone griefing noobs. Of course, I have nothing worth looting so... . Being this new, that's about all I have to contribute to the topic except to add that there are a lot of system messages regarding war declarations and alliance-building and challenges to property holdings.
CRAFTING: Newb quests introduce crafting pretty well. You can make useful stuff from the get-go. High end crafted stuff is sold on the trade channel constantly.
COMMUNITY: As I said, ganking/griefing of noobs is not rampant. Players do answer questions on chat. hash bowl set me up with a set of R30 Assassin's Bows he crafted. Noice! I'm thinking it's because us Orks are a better class of people than the other races.
POPULATION: A little light. The only time I've faced competition for a camp was the noob gobbies just outside Flayed Elf but there are other gobbies around. No competition at any other camp. Still, if you want to be around people, you can find them. Clans actively recruit.
PROGRESSION: Another common complaint is the need to grind skills. If you're going for high-end, competitive PVP then, yeah, you will need to grind. So far, just by playing and having fun I notice satisfying progression. However, I'm not in a rush. I like discovering content.
SERVER STABILITY: Server went down once for an hour or two but other than that, server is stable.
That's about it. If I haven't mentioned it (e.g. sounds, animation) then I probably don't think they're an issue or I really don't care.
For a first game by a new company still working out issues and still adding content, DFO is very nice. Like I said, I like the game. I'm having fun.