I'm on both and yeah, there are a lot of differences.
The main difference is the mindset towards hacking. People on tumblr are more relaxed about it. Most major giveaways take part with hacked prizes (but the majority let you know ahead of time). You'll see that hacked towns are very, very popular on there.
On TBT, it's obvious most people are against hacking. I'm personally indifferent to it. My thoughts are it's your game, you do what you want with it as long as it's not hurting others.
On tumblr, trades can be a bit of a pain to set up because tumblr doesn't always timestamp when asks or IMs are sent (and there's always a chance the receiver may not get your ask). Because of the large amount of people on there, I'm a little weary doing trades since there's no feedback system like here or Reddit. I've had a few bad experiences with people being less than pleasant, but it's such a small number out of so many positive trades. Pro-tip: don't ever let anyone wander and follow them around if they're in your town. (Meanwhile, that behavior is much less common here.) Also, always ask if the flowers are breedable; if they're hacked, they will not breed unless they're in hybrid bags. Always ask if you're not sure.
Most people are pretty nice and pleasant on both tumblr and here. As with any site, there will always be a few bad apples but it's best to pay no attention to them. If there's a bad person on tumblr, people generally try to warn others by letting everyone know.
Overall, both communities are great imo as long as you're following/communicating with the right people. There's a lot of kind mayors on both sites.
