A repeat of the above really, the carbon steel blade takes a good edge but marks easily. If it will get wet (outside in the rain use) or you will use it on cheese (alkaline) or fruit (acidic), it will mark. But it's not like it rusts like your car.
The stainless will look nicer, but you'll spend more time sharpening it.
As for the wood swelling that is true. I took mine apart and lubed it with beeswax.
Also, the 8 is illegal in the UK, unless you have a 'legit' reason to be packing a blade. I think it's the 6 that is the biggest blade and you can't have it locking. Loads of info on what's 'allowed' if you Google it.
But they are good knives, light, sharp and cheep enough you can loose it.