They are completely different games so it's hard to compare them fairly. I found the GoG release of Call of Cathulu to still be very buggy, to the point of having to cheat my way through the first action sequence. I never encountered any bugs in Arcanum.

But again, very different games, it depends on what your preferences are.

I agree with the person above me. The two games are completely different from one another. However, I've never played the latter. Therefore, I may be more in favour towards Call of Cthulhu: Dark Corners of the Earth as it's the only game that I've played between the two, and the fact that the game has done a really great job in setting the atmosphere. Especially, the way the game makes you feel paranoid for being watched by someone (there are some parts in the game where the game completely gives you an indication of someone following you by showing the follower's point of view in real time). The thing is, queer creatures are not the only ones that you should worry about as you play the game.

Although in order to appreciate the game more you might be required to have read some of H.P. Lovecraft's works beforehand, the game is still both enjoyable and creepy without you already knowing the lore of the world that you're about to indulge yourself in to.

Just wait a bit if they are not on sale, and get them both. Not played arcanum, by DCoTE is a great game. Has bugs, and you will likely want the loader for it:
http://dcotetools.sucklead.com/2012/10/version-15-available.html?m=1
Not sure if it works on 64bit.
It peters out a bit towards the end, but there are some cracking moments.

Huh, I didn't realize that it was in the catalogue again. When did it come back?

Both are great imo but DCOTE has a couple of nasty bugs which was never fixed and if i had to pick a game then Arcanum it's a stellar rpg and the better game overall without a doubt.

It was removed before?

Arcanum.

While Call of Cathulu: Dark Corners Of The Earth is interesting and has really a great atmosphere, Arcanum is legendary for its system and setting. Both are a bit hard to get into, but I think Arcanum is a more satisfying experience in the long run.

Yes, just some days after it was released:

https://www.gog.com/forum/general/release_call_of_cthulhu_dark_corners_of_the_earth_b7169/post203

I have Cthulhu as my avatar BUT steampunk wins every time, hands down.

Arcanum.

Three months ago.

Nice! Seems I either completely missed it or forgot about it.

Arcanum. Never played it through personally but my friend circle back in the day loved it and talked a LOT about the quests so there is much meat and potatoes in this one.
The Call game.. played that and it was... unsolveable to me. I just got stuck.

I'd say Arcanum. It's a full RPG with a somewhat unique atmosphere. Expect a whole world, stories, characters. More content, more hours. More like a book.

Dark Corners is just a FPS, even if with a well done lovecraftian flavor, an interesting weaponless beginning, and a cool fright/madness gimmick. I like it. But... it's really a smaller thing, more basic, sooner over. Less meat to it.

Less meat than in a book.

Don't cross the metaphors. It would be bad.

I never played Arcanum, but loved DCotE... I played the original PC version, buggy as hell, and with no cheats whatsoever. I still don't know how the hell I managed to finish it due to the bugs (specially in the MINOR SPOILER "last run", discovered through google is a good idea to hop continously since it seemed the floor was supposed to collapse but never shown or something like that). The ambience is incredible, and if your familiar with HP Lovecraft's work there are several moments of "holy shit... is that part" and stuff like that. IF, and only IF you can take a seriously buggy game and can resist a couple of action oriented bullshit (two parts) and a couple of sneaking sections (also two) which are all mandatory, then yes, CoC DCotE is absolutely worth it. As for Arcanum, I believe I read somewhere it was "unparalelled" regarding role playing character creation or something like that, and the setting seems pretty cool.

So, basically: buggy mess of OMG moments and ambience up the arse, or a not that buggy game with cool setting and role playing.

I would choose Call of Cthulhu, but I'm a Lovecraft fan...