I really like both...
Let me preface my LARP comments by saying that I have never played any system except NERO (ie, no WW/VAMP, etc).
I am going on my 21st year of Tabletop RPGing (with 5 years of board wargaming before that). I was introduced to LARPing back in the early 90s - the NERO Fantasy LARP - which I got interested in after reading an article in Dragon.
I attended a couple of events in 93-94, then life got busy and I stopped going. My gaming group and I decided to give it another try in 1998 and began attending Wildlands South (Part of NERO Atlanta) and had an absolute blast. With 3-5 weekend events per year, intricate plot lines, tons of boffer combats, reasonable character advancement, etc.
It was a perfect adjunct to tabletop and actually allowed us to get out there and "Just Do It"...run around in the woods all weekend, pick the locks, ambush (and be ambushed) by monsters, fight in enormous field battles, fight off assaults on the cabin at 3:00 AM.
I found no animosity among the 75-125 people I interacted with each event towards tabletop. Plus, our entire gaming group (usually 6-9 people) attended each event, fought and adventured as a team...kind of like a DnD party.
From what little I know about WW events, it definitely isn't my cup of tea...but fantasy LARPs are, in my experience, a ton of fun.
I think one reason that some tabletop players might be turned off is that it can be pretty strenuous...a full weekend of running, fighting, spotty sleep, etc can be a pretty big drain. Most (not all) RPGers are not in the best of shape...it's one thing to sit at a table and say "My character does X"...it is quite another to actually have to do it

. For one of the guys in our group, the quarterly events were about the only exercise he got the whole year and he could barely move by the second night

!
Anyone who lives within 5-6 hours of Atlanta and wants to experience and awesome fantasy LARP should check out
Wildlands South
There are events in September and November. Tell 'em
Arturio Duvalier sent ya!
~ Old One