I've had my mill about a year now, used it when first acquired and then quite heavily recently - other events overtook milling as a priority hence the gap.
I found the assembly instructions a bit confusing at times, so look at videos of the kit in use as it's frustrating when you have to dismantle what you have assembled to insert a piece you've missed as the fasteners slide in the extrusion. However, you do get to know your mill setup quite well! I did leave the 'window' thing off as I found it got in the way of the winch but you'll need to decide for yourself
The winch is a must for ease of use and I after purchased the small triangular tang and pin end (Part Number SILVR-WEB) rather than the long aluminum bar/arm thing that came with. Much quicker easier to use. You also avoid the risk of milling the ali bar on the original option.
I have the vertical milling kit but not used yet as I'm still looking for rip chain for my smaller saw so can't comment on that.
The first cut 'ladder' works well but is only 8ft and I'm finding it's too short for run on and run off on the longer trunks so I'm about to use/adapt an aluminium ladder I have kicking about for the longer stuff. As a 2 piece, with joiners, the comes with first cut kit is very portable - which is a plus. I think you can get extenders to make it longer ?
The level adjusters on the first cut can be a bit long for larger diameter trunks and can stick up above the rail so the mill won't slide generally I found them to be a bit fussy in use, either too long or too short, so be aware. I've cut some wood packers to wedge it firm and level. I like the spikes that hold it down, be gentle at first , get it level and stable then drive them home - and check. Don't forget to set the correct milling height to compensate for the rails and then RESET for your actual cut thickness when you remove the first cut rails. (oops!)
I've just fitted the secondary oiler - see review elsewhere - and this is worth the effort as I was concerned my 36" bar might run dry. Best avoided.
Minimum cut I found it about 3/4" ish or about 20mm, I've not gone more than 65mm thick as yet (else slabs too heavy to lift!) Suggest you check the indicated depth of cut (which is in inches) against what you actually get. Mine is under indicating by about 1/4" (6mm ish ) so I set for 2 1/4 " and get a 2.5 inch/65mm actual thickness.
Be very careful when clamping the bar in the mill check and recheck and retighten to avoid getting the clamps anywhere near the bar channel and chain.
During cutting I use wedges both sides every foot or so - I have 4, the back 2 swap to the front to wedge the new cut , rinse and repeat along the cut to prevent pinching of the bar.
Obviously the mill gets to be quite a lump with a large saw and bar attached and starting the saw in the rig is fun and games.
The other information and videos on the chainsawbars site is excellent and very useful too.
Overall very pleased as a hobbyist woodworker harvesting my own felled trees, this rig at this price point is excellent value.