Small Fixed Gantry Router Spec and Build

[JAZZCNC]

Well first have you priced profiled linear rails from china yet.? You may get surprise.!

5mm or 10mm pitch makes no difference to price they cost the same. There would be more down side to using 5mm than 10mm.?
Smaller pitch would give you higher resolution but this comes at the cost of speed and to some degree torque. Higher pitch will give you half the resolution but twice the speed.
Now the main difference lies in torque or more importantly more torque where it's needed which is while cutting. The higher pitch means for the same speed the 10mm will allow motors to spin at half the speed of 5mm. Now because steppers lose torque as rpm increases the available torque from motor is higher because spinning half the rpm but the cutting speed is the same. The main loss is in resolution but even with 10mm pitch you'll still have more than enough resolution for 99.99% of work you'll do.
5mm pitch does provide more mechanical torque than 10mm but still it's motor rpm where it's needed most and 5mm will mean the motors while cutting are spinning near there speed curve threshold where torque drops away fast which isn't good. 10mm will surve you much better and give more flexibilty.

Regards Digital drives then yes they work just the same. If you want to see how shitty analog drives can cripple machines and people not even realise it and also the difference digital drives make then I recently posted a video showing it. Can't remember the post but do search and I'm sure you'll find it.