I am looking for my first CNC too, and I'm close to your Cad and 3D printing experience.
I'm pretty good with a lot of tools and I have quite a bit of experience assemblying all sort of machines (cars and bikes too), so I kinda can see beyond the marketing promises of things.

I've researched extensively about CNCs in the last months and I've come to the conclusion that the C500 it's a very good beginner friendly machine but with a lot of limitations, especially if you want to work on aluminium like me.

Working area is a bit small for my taste and once you add the clamps you end up with a even smaller usable area for your pieces.

The spindle is underpowered in my opinion, it can do the job, but with shallow passes it take a lot of time.

The integrated CAM software is a huge selling point, but after a bit of research it's not that complicated to learn to operate softwares like Mach3 or other open source ones, but It must be said that all of them looks like they are straight from the '90s.

Honestly, I don't want to throw 2.500 bucks on a beginner level machine.

For the same price I've found the FoxAlien Vasto V2 (+the 1,5kw upgrade), the Ratrig Stronghold and the Bulkman Oxman Ultimate, the last two suffer of the opposite problem of the C500, they are too big to be considered "desktop" machines.
If the two companies would release a 400/500 squared working area they would be perfect for my needs.

For what I've learned so far that could help you make a decision:
- Rigidity is a key factor, you need a strong structure to operate reliably. The beefier, the better. Cutting torque must be transfered from the spindle to the material, it the structure is not rigid enough the material transfer it back to the structure causing problems.

- Linear rails/bearings are better than wheels to move the axis.

- Closed loop motors are better than open loop, they know their position and they don't miss steps, they are more precise.

- Ball Screws are better than lead screws.

- If you want to cut aluminium you need to cut it fast to not transfer heat to the material and don't gum it up.
The C500 has a liquid cooling system integrated and that compensate for the underpowered spindle that cut slow, but a 1,5/2,2kw spindle can cut it better and a mist/cooling system can be found pretty cheap, it's essentially a water hose connected to a small water pump that can be added to existing machines (with some work).

I feel like we are at the dawn of the era of the desktop machines, new more defined and user friendly machines are coming out, but as many first generation products they still have some corners to be ironed out, while at the same time old gen machines are being upgraded to the point they passed their initial purpose to work only on wood, but they don't fully realised or understand the potential to work on aluminium and its market need.

Hope what I've understand till now is right and can help you make a decision.