I think there are 3 main differences between the Founder's packs, how much value you put into the differences versus the real life money spent is probably subjective.
1> Alpha/Beta/Closed Beta Access. Alpha gives you 24/7 servers available to you. So if you either want to play this game all the time or don't have the time to devote certain weekends for the beta event then there's that for you. I'm assuming the middle pack means that there will be a permanent closed beta server at some point but I have no information on that.
2> The Patron status duration. The game is F2P but like Rift, LotRO, and countless other F2P games there is a subscription like option that gives you some more bang for your buck if you decide to play this game a lot and intend to spend some money in the in game item shop. It's 90/60/30 days.
3> Extra coins to spend in the in-game money shop and the glider. I have no clue what the money shop will include since it's not active currently in Alpha but I can tell you that it's kind of a hassle to put together a half way decent glider in game at the moment lol. Now the basic glider you with lowest Founder's pack is no big deal because you get a basic one at like level 12 in the game too. But the nicer glider takes a bit more time to put together.
I agree with Laskmi that if you're only casually interested in the game, then subscribing for the basic Founder's pack is good enough since you can play the game during the closed beta weekends. Then again, if you decide you love the game and want more access, I am not sure if you can upgrade your Founder's pack afterwards.
It IS a fun game. There is a lot to do and I think it has broad general appeal due to the sandbox nature of the game. I think most people will find something to amuse themselves with, at least for a little while. I've wasted so much time doing non-typical MMO things in this game lol. Part of it is that it's Alpha and I feel no rush to level but part of it is that there are lots of almost minigame like things to do. My latest thing was purposefully stealing something so I could go to jail and then attempt to break out of it. Sure it wasn't as fun as I thought it might be but it's still amusing to have this available to you in a video game lol.