Hi, and welcome! I see nobody's replied so I'll share what little I know.
I can't speak to the fenix light, but all of the quarks I've seen have beautiful beams with no dark spots. However you say you want a tighter beam, and the current quarks - due to properties of the XP-G emitter - do have fairly large beam centers (hotspots). Beautiful, but maybe not what you want.
For Quarks with tight beams you'd have two main options: either a quark turbo (head is designed to give a beam like you're requesting) or an older run quark with the XP-E emitter.
That leaves you with
Quark AA² Turbo
WARM WHITE Quark AA² Turbo
Quark AA², R2 Edition
I really am liking warmer tinted lights right now and would recommend that warm white turbo, but it's a personal thing and you may prefer the cool white of the other two. The warms are not quite as bright as the cools, but still very bright.
If you
are still considering the regular and tactical quarks, the only difference between them is the user interface. The following two threads discuss the differences and some rationale for preferring one over the other in different situations:
http://www.candlepowerforums.com/vb/showthread.php?t=267730
http://www.candlepowerforums.com/vb/showthread.php?t=240105
What I got out of them was that the regular quark gives you easier access to all seven modes (5 brightnesses and two blinkies) which some people prefer but you may have to cycle through modes more often than you like to get where you want, whereas with the tactical you select any two of the modes ahead of time and program them for instant access, but accessing the modes you haven't programmed is a little more burdensome. Tactical has forward clicky switch (momentary-on works, you can signal with it, etc), regular can stand on its tail. It's all in the threads.
I hope that helped a bit.
-John