Both have their ups and downs and some people are just fanboys or butthurt by everything.

Obvious thing is obvious :

War Z is a standalone game while DayZ is an Arma2 mod.

PS. Real world money for "special" weapons for a game you need to buy? Faggotry to the max.
Skill/level system is kinda lame also for such game ._.

^Wait. On your PS...what game are you referring?

WarZ , sounds gay as fuck now. HEY YOU ARE IN A ZOMBIE APOCALYPSE BUT YER CAN LEVEL UP AND SUCH , ALSO BUY WEAPONS WITH RL MONEY KK?

A REAL survival game should have NO leveling systems (no +1 armor etc. in stats). and NO stuff which you can buy with RL money.

Obviously doesn't know what he's talking about.

Leveling/skill tree = lame? How in the world is leveling up a couple abilities like being able to run longer/faster lame? That builds diversity which people would have in a real situation. And if leveling added +1 armor (not that I've seen anything saying there is anything of the sort), who cares? Some people can take more hits than others. The game is about realism, I fail to see how some people being stronger, faster or overall more durable isn't just like in real life.

Also the "weapons" you can buy in there are just basic melee items that are easily found. Not to mention you die and drop them. There are also no guns or anything in the shop. It's all just basic stuff.

On top of that, Day Z isn't (or rather, won't be) just a Arma 2 mod because they're building a standalone client.

I've never played Day Z, but just from what I've seen I'd prefer War Z. And since I am currently playing War Z I may be a little biased, but trust me I have plenty of complaints about it as well. If only we were allowed to record shit of the game I'd have tons of videos explaining bugs, awesome stuff, and stupid shit (cough ridiculous pvp). But alas, there is a Non Disclosure Agreement until November 5th... We can't even take screenshots. I think its probably so the world doesn't see how shitty some of the stuff in it is xD. At the same time it's still a ton of fun even with the shittiness.

Also on the scam part, it almost seems like one at first. About 99% of the features they said were in the game.... aren't in the game. They said for alpha they'd be cutting down the map size and the amount of players per server... They said nothing about limiting character customization, removing a ton of features and suddenly a zillion bugs coming. It almost feels like those things were never added in the first place even though there are "videos" of it. But every day brings a patch slowly bringing the game to the advertised glory.

I haven't played War Z so I cannot judge it wisely. Are the zombies running? Do their animations a lot better than Day Z? You have a point about the skill tree but I hope they don't exaggerate it. Running faster/ longer stamina is a fine. and skills like strong stomach(can live without eating for few more minutes) or such but I hope they don't give us gamebreaking skills though. That would ruin it.

So i'm gonna give my own opinion on both games after playing it for a little while

Warz : Quiet fun, graphics are better, better city's, building blockades etc. but at the same time a lot of exploits, bugs, weird animations. (Yes yes this still is in alpha and is getting better by the day)

Dayz : Tons of fun, Better animations, PVP flows better for me but as said in the above, alot of exploits, bugs and some weird animation (Again, in alpha)

Some people are still complaining about the amount of hackers in DayZ. While there still are a lot of hackers on the main servers, the smaller private servers are having no such problems. I've been playing on one for about 4 months now and haven't had a single hacking problem on the server EVER. The key is to find a server with an active admin and with a good community (That's the icing on the cake if your lucky)

It's gonna be down to what the player really wants.

I enjoy a full real life scenario like DayZ (Not that WarZ doesn't give the same feeling), running through a huge map, picking up small items from town to town, meeting up with someone or having an epic sniper pvp with someone at NWAF.

In the end both games are gonna continue improving and still have their own flaws

Hope this helped out a bit