Got the jacket in today, so on to the comparison. It should be noted my genuine MK3 was bought used and came with a lot of natural wear and distressing.
At a glance or to the uninitiated, it would appear as the same jacket, but looking closer this is what is present/not present on the Alpha vs the MK3:
*No shoulder epaulets.
*Zipper runs fully from the bottom hem to the tips of the collar.
*Zipper tape is not free floating on the last few inches as it is on the MK3.
*Zipper is a dual zip allowing it to be unzipped from the bottom up, but it is not an escape zipper.
*YKK metal zippers, brass.
*Collar shape is smaller and not correct.
*Missing the vertical stitch pleat below the chest pockets visible on the MK3.
*There is no hidden hood behind the collar.
*D-Ring tab on the chest is about 2 inches lower than on the MK3.
*Wrist tabs are more pointed shape,
*The neck closure tab is longer and narrower. Retention loop under the collar for the tab is identical to the MK3.
*Small side entry pockets have been added at the waist, pocket bags are small.
*The pen holder is not padded or doubled fabric as it was on the MK3.
*Buttons are the wrong color, they are also slightly bigger and coin shaped rather than the taper on the MK3 buttons.
*No interior pockets, but neither does the MK3
*Zigzag stitching on the storm flap and under the collar, not present on the MK3.
*No seat warmer panel and loop on the interior back of waist as visible on the MK3.
*Waist adjustment is a ribbon similar to the pull ribbon found on an M-65 field jacket as opposed to paracord on the MK3.
*No underarm gusset as present on the MK3.
*Two sleeve articulations on the back of the sleeve that are not present on the MK3.
*Sleeve cuffs have gussets above the adjuster tab.
*Fabric is a 55% cotton 45% nylon ripstop, it does not feel cheap, but definitely doesn't feel as tough as the fabric on the MK3.
*No evidence of the honeycomb insulation found on the MK3 interior.
*Lighter weight, likely nowhere near as warm as the MK3.
My evaluation:
Retails on Alpha Industries for $300+shipping, on par with what I paid for my MK3 back in 2012.
A fairly decent repro considering its a mass production off the rack item.
Would need a substantial amount of work to get the collar accurate and adding the epaulets to the shoulders.
No idea how well it would take dye, but then I've heard the MK3 can be tough to dye.
The side handwarmer pockets are a nice addition, as the regular pockets are really more for storage than putting your hands in on the MK3.
After hand stitching the compression lacing on the sleeves of the MK3 because I couldn't find anyone local that would take on the job, I can say the Alpha jacket's material is likely to not be as difficult to get a needle through it.
Build and stitching quality is on par with any other Alpha Industries jacket I own and should work fine as a light to mild cold weather jacket.
The biggest plus for me, is the sizing options, as even before I chonked up in the gut, the MK3 I got (Size 7) was already a 'suck in that gut' to get it zipped.
If you're looking for screen accuracy, the one ID10T linked is a much better option if you can't find an actual MK3. If you want a jacket that has that aesthetic and is easier to size up or down and the price point is ok with you, this fits the bill.
Verdict: 3 out of 5 facehuggers