I was just curious and searched for corexy design 3d printer from Ebay and found cheap Tronxy X5S.

Some reviews praised the mechanics and bashed electronics. As electronics and software are things which I'm familiar, I wouldn't worry about that.
Most reviews were just hidden advertisements or someone having fun with a new toy.

Has anyone tried those machines and given the analytical engineering look? Specially to the mechanics.

I have been looking at x5 as a fast addition for another printer.
have found a very few "honest" reviews on youtube. Looks like it needs quite a few mods just looking at it.
Those reviews confirmed that.

Still looking for a fast addition to the fleet. But can't find one cheap that seems to work decent... Go figure..
Best buy seems to be a cr-10 or a variant.

Think I have to step up progress on my core xy project..

I have a couple of TronXY bed-flingers, a X3A and X3S.

The kits are reasonable value to somebody who can tinker, due to the extruded aluminum V slot.

On board is a Melzi without a bootloader, the other is a "lonestar" labeled board that is similar and may have a boot loader, but don't quote me on that.

The 12" bed on the X3S is not flat enough to use without bed level compensation, but the little 8" printer is great. (I also upgraded to E3D v6)

Both printers required a bit of fiddling around, (Mostly shimming), but are reliable after that because of the decent frame. That is what sets them apart from the basic Anet acrylic framed printers etc.

I have the X5s, and love it to bits now I have printed a number of fixes and tweaks.
I come from a diabond Mendel90 (awesome machine) and a 3DR delta.

Bad points
I bought the X5s, there is now a X5sa (or something like that with a touchscreen, filament run out monitor, etc...)
The frame needs stiffening
It needs a new hotend (I went with the obvious E3d v6)
The belts need realigning via a printed mod (think the new model has done this)
A better extruder would be a good mod
I have the original electronics, they need to be replaced if you want to add anything fancy like bed levelling without losing elsewhere. (new model might not have this issue)
Bed is so big you need to stick a 24v psu on it or mod it to something different.

Good points
It prints big, this thing is a monster, and they now do a 400mm version!!
Even without mods my prints were pretty good.
I love to tinker and although some is needed I love to keep on improving.
The build is very easy.
Plenty of people have bought them so a lot of parts are on thingiverse, and videos on youtube.

I wouldn't change mine apart from I should have waited a month and got the updated version, but hey thats life

I have an X5S (330*330*400) and have just ordered the X5S-500 (500*500*600). As other have said they are a good starting point if you don't mind tinkering. The belts on my X5S were aligned correctly when I received it and I agree with reinforcing the frame. I have replaced or added the following on my X5S:

6mm steel core belt to 6mm fiberglass core belt for improved flexibility
All pullies have been replaced with either smooth or 20t pullies as appropriate. The printer I received had washers and bearings rather than pullies.
Hot end (installed E3D V6 clone) and cooler. For the cooler I used the Petsgfang V2 from Thnigiverse.
Upgraded the power supply to 24v 20A and resoldered the bed for that voltage.
Replaced 12v fans with 24v fans.
Added MOSFET's for both the bed and hot end.
330x330 borosilicate glass with high temp silicone interface.
Mod to enhance the rigidity of the carriage on the extrusion.
Duet3D 2 Ethernet with 7" PanelDue.
Added authentic Bltouch.
Anti-backlash string loaded nuts for the platform.

Here is what I plan on doing to the X5S-500:

6mm steel core belt to 6 or 10mm fiberglass core belt.
Convert X and Y to linear rails.
Replace the pullies with either smooth or 20t pullies as appropriate if needed.
Hot end (install E3D V6 clone) and cooler. For the cooler I used the Petsgfang V2 from Thnigiverse.
Install Titan extruder clone.
Upgrade the power supply to 24v 25A and resolder the bed for that voltage.
Replace 12v fans with 24v fans.
Added MOSFET's for both the bed and hot end.
500x500 glass with high temp silicone interface.
Duet3D 2 Ethernet with 7" PanelDue.
Add Mini differential IR height sensor.
Anti-backlash string loaded nuts for the platform.

Thanks,

Tom