I have both, though I must qualify that my SKSes are all Russian ones 52-54, while the WK that I have is generation 1.5. That does make a big difference in my view, and would lead me to lean towards a preference for the SKS...here's why (and this is just one old fart's opinion).
SKS Pros:
1. Impressibly reliable given its age. Never had a feed or eject issue.
2. Fun to shoot - self explanatory - my lukewarm-to-guns son loved shooting it. My SKSes (I have 7) are second most frequent guns brought to the range.
3. Gun is relatively cheap, unless you are buying a collectors' grade one
4. Ammo is cheap, with choices of non-corrosive or corrosive
5. A must have for those who love history or like sentimental stuff. Things like coming with oil can, ammo pouch, etc. may appeal to collectors.
6. Easy to operate. I would go so far as to say almost flawless operation.
7. Easy to take apart and reassemble
8. This isn't really a pro for me, but I know others it is - it can be sporterized and therefore customized for more modern aesthetics and accessories. Make it look like an AK, or whatever strikes your fancy.
9. Great rifle for beginners - aside from operationally, having new shooters train with iron sights is a good practice to learn fundamental shooting skills (in my opinion) rather than the ease of using an optic.
SKS Cons:
1. Must check to see if the firing pin rattles. If not, you may be subject to a slamfire. It is easy to take apart the FP and clean the channel to prevent this. Similar thing to look for is seized sear due to gunk accumulation in the trigger assembly.
2. Reloadable 7.62x39 rounds are more expensive to shoot, all things considered
3. Legally stuck to 5 round limit - so no way to use a 10-round LAR15 mag on it
4. Can get fleeced by sellers who don't know enough about SKSes and claim it is all original, unfired, unissued, etc. I just had a CGNer just last week claim his SKS was non refurbished, and sent me the photos - I told him where the refurbishment marks were in the photos and told him what the original parts would have looked like based on the year, etc. You'd be amazed how many people are convinced they have a mint conditioned, unfired, unissued and unaltered rifle, when a cursory glance will easily reveal otherwise.
5. The SKS is not a tack driver, so don't expect to win accuracy competitions
6. Nowhere to put optics, especially for old guys with bad eyes (just sayin')
7. Always need to check the condition of the gas tube/piston rod. A impeccable exterior stock/receiver may not reveal that the gas tube / piston rod is seized due to non-cleaning after incessant use of corrosive ammo (I found this out the hard way in buying on previously). This can be fixed, but something for any buyer to consider.
Now, for the WK-180...again, my experience is purely with a generation 1.5 (non magnetic CH as in G1, but not the HT threaded one)
WK180 Pros:
1. Modern semi-auto sporter
2. Takes LAR15 and AR mags
3. Decent accuracy out of the box (at least for mine)
4. Excellent customer service - when I stripped my handguard screws, I just wrote them and the next day a new set was sent out to me. I wish they would send me a better/improved CH though (see next section)
5. Relatively easy to take apart and clean.
6. Canadian made - I know for some people, they may not see that as a plus, but I do, insofar as service, etc.
7. You can buy it in a couple of calibers.
WK180 Cons (again, based on my 1.5 gen)
1. Charging handle constantly loosens with use. Even with putting a metal rod through the CH holes and turning with all my might, it loosens. Yes, I can loctite it, but I clean it often so prefer not to. Yes, I know Spectre sells/sold the improved HT threaded charging handle
2. Worksmanship is iffy. Whole thing rattles like my 15 year old Japanese SUV vehicle. My handguard screws loosened over time (6 of 8 of them). I also dodged a bullet but checking the gas block screws on a lark and thank goodness, noticed they were super loose and I tightened them, with loctite...which leads me to...
3. Common problem on this one is broken gas piston rod...almost guaranteed to be from the often-reported loose gas block screws. Also common issue is sheared threaded charging handle from Gen 1.5)
4. No last round bolt hold open / bolt release (yes, I know they fixed this in G2, and TNA has a kit you can retrofit Gen 1 - 1.5)
5. Could use brass deflector so as for ejected rounds to not mar the finish of the receiver. This is purely aesthetics, but still annoying.
6. More expensive than SKS...the Gen2s are significantly more expensive. In my opinion, WKs are overpriced, irrespective of generation, for what you are getting.
I am sure I could think of more and may add to the list as stuff comes to mind but that's it for now...