I have an f7 sbt he's 17lbs! He much bigger than my F5b.
Later gens can get large too. My F7 is soooooo stubborn but yes very, very loyal! I swear my F7 has a lot of traits of higher gen cats. A friend of mine has an F3c we visited over the spring he's teeny tiny compared to our f7 so size isn't necessarily by generation. Our later gen is huge.
When we got Jengo I was in the same boat as you wondering how a later gen would be and assumed he's be more mellow. Not true. He is a very hyper cat only mellowing out now and he seems mellow because we got a new baby. As I play with my new baby I remember just how playful Jengo was and still is. Neither cat likes water although Biz my f5 probably will eventually like it - I can see him getting more comfortable wih the sinks, showers and tubs.
They are both trouble makers but in different ways.
My F7 only loves me and tolerates everyone else. Only since getting biz does he even warm up to anyone else. Competition is a good thing
he's really smart.
Neither of my cats play fetch because they are really ADD. I've managed to train them to eat food and poop. Woohoo! Lol!
Common traits between the two kitties: hyper, playful, love treats like will do anything for treats, talkative, emotive, sweet, intelligent, curious
Both cats have learned to respond to "no" but they are sneaky oh so sneaky, they will out smart you and keep you on your toes. Don't let them get near the paper towel...
They are cuddlers when they are sleepy or hungry but mostly sleepy. They are are hilarious! Each cat is really different. I recommend lower gens all day long but warn they are much more exciting than your average cat
We thought about getting a higher gen too but F1's and f2s were oh of our price range. I'm glad we looked to lower gens they've made our home insane, hectic and fun.
I would say aside from personality traits the biggest difference between my f7 and f5 is markings. Jengo is a silver and his markings are not as bold as Biz's but biz is brown so to could the difference in color or because Jengo is a later gen. Not sure and I've seen really dark and gorgeous markings on f7s and more muted markings on F3s it all depends on out crosses and genetics. I personally don't care that Jengo doesn't have dark markings because he is him and he's spent 2.5 years making me laugh and love like I didn't know I could.
Here's a link to Jengo's Facebook page if you're interested in seeing more of what life is like with a later gen.
https://www.facebook.com/JengoPet