I'll tell you first hand, winning this league is the greatest feeling you can experience (fantasy wise). You feel incredibly satisfied after putting countless hours into ranking, drafting, trading, and managing. Then there's the relief knowing that the first title you've won is out of the way. Even when you're a top contender, the probability of winning is a crapshoot. The best team could end up losing each year, and eventually get shutout completely as their window expires. We'll see long title-less droughts in this league, so when you're able to win it all and pop your title cherry, you appreciate it that much more.
The euphoria you experience over the course of the playoffs is amazing. You win that first matchup and it starts to sink in that you're only two more victories away from the title. Then, you go right down to the wire against another tough opponent and pull off another win. Reality checks in that you're only 7 days away from being the champ if you can beat one last opponent. Then there's that last Sunday, oh my, that last Sunday.. D-Day. It can make or break a season (as it did for me in 2013). When the last pitch is thrown in the last west coast game, and you refresh the scoreboard one more time and see you just become the champion.. it's nirvana.
Now picture that, but after years of rebuilding. I imagine it would be even more satisfying.