Can some of you give your thoughts on the major differences between the 2 divisions?

Division 2 is my favorite. But that isn't what you asked.
D2 is easier to recruit. Almost Never does a 1AA team drop down to take a top D2 player. But that happens all the time when a 1A team takes your best recruit in 1AA.
When I played 1AA that was the biggest difference. I haven't been in 1AA for years though.

Depends on the World mostly IMO.

Recruiting:

For large human populations, I prefer 1AA. The recruiting challenge in 1AA is extreme and much harder than any other level IMO. I find this challenge very satisfying for me personally. For many, it is very frustrating.

Div II is easier to recruit only because of the lack of "drop down" events from the higher tier typically.

Playability:

Gameplanning is the same no matter your level. You need to be a great gameplanner to win NC's. You can be average and still be top 10'ish every year with good recruiting.

Some say you see greater growth at II than at 1AA, but I do not notice the difference. Development is still one of the most important skills in the game. I think the difference between an average potential recruit and a good potential recruit is more pronounced in 1AA, but that could just be my personal perception.

Overall:

1. I like 1AA best, but I play in Wilk...and there is nothing else like Wilk in GD.
2. If you do not like recruiting, or find it frustrating to battle often....then you should not play in 1AA...II would be better.

I generally agree with the above comments. The recruiting is the only real difference. The "dropdowns" from D1A can be a real pain in the ***. However, with that in mind...they don't always take the guys that you think are the best. This can result in you getting few really big studs and those few guys, if you do get them, will make your team for you. You cannot really get "gems" like that at D2.

Generally, D1AA is not very populated so you can make some noise pretty quickly. If I remember correctly, there is no more "vision" issue at D1AA...I think you can see the whole population of recruits at that level.

So, its a pain in the butt, but can be a very rewarding thing.

I think D1AA is the quicker path to an NC due to the situation mentioned above. Top tier D1AA teams have to deal with D1A teams dropping down and grabbing recruits from D1AA. There is overlap between the vision of the D1A team and the upper D1AA teams. If you have top vision in D2, you can work the top layers and not have any fight. But, if you are a team that's building at D2, that's something you have to overcome and it takes time.

A lot of patience is required recruiting in D1AA. You don't want to spend all of your money early, just to see a few D1A teams drop down and take all of your players. If you play your cards right and wait to see which of the good players the D1A teams are passing on, you can really get some high quality D1AA studs.

DII is the best in the game IMO. The only weakness to D2 is that the competition for top recruits is low because of vision and the fact that D1AA don't take players from the primary pool of players. I just wish they could combine several worlds to get higher populations to make the recruiting portion of the game more challenging in terms of battles etc.

Every division has it's pros and cons. I like that all the coaching features are unlocked in Div 2. I also like the potential of a 19 game season = Less downtime. Div 1A has a much longer downtime.

Compared to Div1A though, the football simulation part of the game is much weaker at Div2. Coaching seems to have a bigger impact because the football sim side of the game is more realistic. I hate that at Div2 a Dime defense is able to stop a Wishbone or NDB offense from running the ball., just because of a talent disparity.

Div 2 you are rewarded by playing a cupcake schedule (sims). You are penalized for any loses.
Div 1A you are rewarded by playing humans. In fact a loss vs a good human team will have you higher ranked than a win vs a sim.

Div 2 recruiting is fairly easy. Especially after you are established.
Div 1A recruiting is a real grind (at least for me.)