I played hundreds of hours of 'classic' first time round from around patch 1.4. 5 or 6 lvl 70s up to WotLK. Some of my most fondly remembered gaming experiences. I could not get into 'classic' this time though no matter how hard I tried. The grind was just far too boring and monotonous. I even paid for a lvl 58 to do TBC because I couldn't be bothered to get past lvl 40, and I gave up on the second questing zone of Hellfire. I really thought I was going to fall in love all over again but it just bored me to tears.
As for Retail, I stopped caring when to stay relevant in the game you had to log in and do 2 hours of dailies a day. Plus I hated when they added transmogs in and gear appearance meant nothing anymore.
Time required is the most notable con in WoW in my opinion.
I played a lot of WoW and at one point you realize that time required is crazy, it is a second job, for this reason, I stopped this game. I would never start WoW like now, but my best advice for you (if you want to start the game) is to go for the classic. The time required is less.
Well, if you don’t know anything, start with Classic and then TBC as retail went through some world iterations.
Keep in mind though that both Classic and TBC have been optimized by the community and don’t really reflect the state of vanilla. Also raids will require more effort, so if your only goal is sight-seeing, then I would just solo raids on retail.
That said, you get access to everything with your subscription and don’t have to pick one.
Subscribed for a month - it's a fun game, smooth gameplay paired with cozy music, pleasant landscapes and PvE/PvP activities but probably won't extend my subscribtion.
While I enjoy my time in Tiragarde Sound with my Hunter, named Tovie it feels like that the endgame - which is pretty close since I'm already at level 40 - will be a time consuming treadmill to grind for better gear and scores and that's just not for me.