I have 2 limited data points.
I bought BP in 2008 and it had great depth of player analysis and player comparisons, i.e. PECOTA spits out who a player's closest historical comparables are with their percentage matches. That said, their projections weren't great and they really weren't fantasy oriented.
I bought Shandler's Forecaster this week and it's been a good read, very focused on projections, and very focused on fantasy. However, the analysis seems limited to making simple percentages or ratios and then telling you how they're not totally garbage because they predicted the right pitchers forty percent of the time versus say twenty percent of the overall pitcher population or whatever. Point being, I'm not sure if they've ever heard of a regression but they tweak and torque the numbers in the ways that they do and they claim they do better than random chance.
To sum up, if I wanted to understand players and understand baseball, I'd buy BP. If I wanted to win a fantasy league, I'd buy Forecaster. But then I'd probably buy BP afterward anyway because I would feel like I only had eaten sweets and no meat.
0-3 to 4-3. Worst choke in the history of baseball. Enough said.