I'm currently on level 3, so I can offer you my experience of this season, but please don't take it as advise.
I've noticed on level 3 that the standards of the various leagues varies a lot. Some leagues look much tougher with higher Q teams than others. Wait and see what your opponents look like before you decide anything.
Competition for good quality players in the transfer market also seems much tougher than on level 2. I must have lost 30 or 40 tokens in the first few days of this season bidding on players, some crazy bidders out there. I did manage to win a few new players in the end but I was bidding late at night early in the morning when things were quieter. I only get tokens from the vids and offers etc .. so it really hurt to lose these tokens on the bidding process of the early season.
I quickly found out that my team which did well in season 2 was no where near the standard of the top of my level 3 league. So I sold off a lot of players early, which meant I didn't need a bank loan. This is the first season I've brought scout players as well, simply because 50 tokens and market value on a player is a better deal than bidding 2 / 3 /4 million over the asking price for a player, as i've seen lots of times now in the transfer market. (50 tokens is about 3 or 4 days worth of video watching, form filling for me, but least I know the player is mine when I spend them.)
Just over half way through the season and I'm sitting 5th in the league but still (I hope) in with a chance of winning it. My team quality is just under 35. But, I do think I'm in quite a hard league as i've seen other level 3 players walking away with their leagues with team qualities of under 30.
Just my experience so far this season of level 3 ))