The following isn't particularly intended to sway you one way, or the other. It's intended more to be an objective/unbiased comparison between the 2 set-ups you've proposed.
Primarily, I'm trying to address the "Is there anything else?" portion of your post.
First, you're ultimately going to add a Wise to either machine. So, I'm going to jump past the drop-weight/crank aspect, since it isn't overly relevant in this instance.
Second, if you stick with your X-6FC, you're going to add a stand to it. Ultimately, you're going to have a stand with
either machine. Another aspect to skip over.
Third, the Neos 1000 (with it's glide bar clamps)
will be more of an issue
if you plan on stringing tennis racquets with fan-shaped mains (so, this would also include the vast majority of racquetball and squash frames too).
The X-6FC (with it's swivel clamps) will be much more pleasurable to use when working with strings that don't run parallel to each other (aforementioned fan-shapes... or, God forbid, a PowerAngle racquet). After all... swivel clamps are, universally, the more versatile breed.
The swivel clamps will also be a
little less fumbly if/when you use patterns that alternate clamping mains/crosses (i.e.
Around
The
World patterns or Box patterns).
With the glide bar clamps on the Neos, yes... you would need to manual switch the orientation of
one clamp/glidebar. This is
not a big deal (and frankly, is made to sound, by many people, like some arduous task

). It's not. It only takes about 6 seconds to make the transition. I never understand why many folks make this sound like a big imposition.
Keep this in mind... the normal scenario, with glide bar clamps, is that all racquets will have you transitioning from mains to crosses... but only
once (so you move 1 clamp/bar
only 1 time).
Even if you choose to use an ATW pattern, you would only have to make this transition
2 additional times (you move 1 clamp/bar a total of only 3 times)!
Hardly the headache that is often made of this simple maneuver.
I've even done Box patterns (switching from mains to crosses 12 times) with a glide bar machine and it
still isn't any kind of ordeal.
Sure... the swivel clamps make these (mains/crosses) transitions a little quicker.
However... in my opinion, the differences between glide bars vs. swivel clamps, regarding how you'll cope with fan-shaped/non-parallel strings, is a
much bigger issue to contend with than any ATW/Box patterns are.
In other words, what I'm saying is...
if you do decide to go the Neos route -
don't even take into consideration the so-called ATW/Box patterns "issue" (it's not an issue), but
do take into consideration whether or not you see yourself stringing racquetball racquets, squash racquets, or snowshoe/granny tennis racquets (fan pattern mains).
This is where you will have a much more noticeable appreciation having swivel clamps.
Fourth,
if you get a Neos, you would gain 2 things that you won't have with an X-6FC on a stand.
- Much more tool tray space.
- A brake to lock the turntable in place.
Only you know if you'd find the turntable brake useful or not. Some do, some don't. Many people have a brake on their machine, but don't use it.
On one of my machines (happens to have glide bars), I have a brake, but never use it.
On another machine (happens to have swivel clamps), I use the brake for all sorts of things (mounting/unmounting, tightening knots, final straightening of strings, and when using a calibrator). However, I never use the brake (on any machine) for stringing O-port/EXO3 type frames. Why? That's another conversation, for another time.
As
@loosegroove pointed out in post #6, with it's 2pt. mounting (and therefore, no side/shoulder supports) the Neos 1000 has less metal directly in your way (for you to work around... or catch string on) or side grommet holes being partially covered.
In addition to the already "uncluttered" working area described above, another point that hasn't directly been mentioned, is also how unfettered things are while stringing the crosses on a Neos 1000. By that point in the process, you only have one glide bar in play, one string clamp in play, AND no side/shoulder supports in the way.
Any 6pt. machine with swivel clamps has a touch more "crowded" feel (the smaller the racquet head, the more this is noticed). Both swivel clamps are still present/needed for installing the crosses AND you have the shoulder supports there too.
Not the end of the world... by any stretch - just has an overall less "roomy" feel when you're on the crosses.
Not a "deal breaker"... just pointing out subtle differences, for the sake of completeness, that could be easy to overlook until one has
used various types of machines.
One last thing to bring up (that hasn't been mentioned yet) is being able to center the racquet's hoop (in relation to the center of the turntable).
Some folks feel this is important, some don't. Maybe you care... maybe you don't... maybe you've never really given it any thought.
Personally, I like being able to center the hoop on my machines.
- Like your X-6FC, most machines (but not all) allow both mounting towers (head & throat) to be individually adjusted (towards or away from the center of the turntable). Therefore, you can always center the hoop (provided you adjust each side evenly).
- Some machines (like the Gamma 5003, 6004 and 8800) even have a self-centering feature (designated as "SC") which always and automatically centers every racquet's hoop with the dead center of the turntable - by merely turning a single knob (located at either end of the turntable).
- Lastly, some machines (like the Neos 1000, older Gamma 4000 & older Ektelon machines) have 1 of the tower mounts in a fixed position (typically the 1 for the head of the racquet). You can only move 1 tower (typically for the throat) towards, or away from, the center pivot point of the turntable. Yes, that's one less adjustment to have to fool around with when mounting each frame... but, at the expense of not having your hoop centered (unless you're lucky enough to happen to have JUST the right size hoop mounted).
As you've quickly figured out, all machines have pros & cons.
And, as
@mischiefalex eluded to, it boils down to personal preferences and which features/aspects YOU consider important.
Cheers.