It's hard to tell.. I mean in general, both are high energy herding breeds and by many descriptions would fit the "not easy" category.
but in the generallist of general traits.. I'd say that there are a few differences/preferences that make people think that BCs are easier for THEM (albeit not easier in general) I did some research when I was choosing between breeds and heres what made me pick aussies and spoke to a lot of owners and here is kind of what I gathered..
- Seriousness towards work. I think it was said at some point on this forum "Aussies think everything is a joke, border collies think nothing is a joke" of course both have moments of seriousness/playfulness but in GENERAL, I have found that aussies "natural setting" is fun/comedians, and border collies "natural setting" is more serious. Both are serious when working, but border collies just seem to think they are working a lot more often lol
I find it much easier to work with Merlin in all his happy silliness
to me, training is a game so his temperament suits me
but to others, a more serious demeanor might be easier.
- Natural movement. Border collies stalk, aussies bounce. I love how bouncy Merlin in, he is like a little bunny rabbit! I see how it would drive some people nuts.
- Handler forgiveness. Border collies tend to point out handler mistakes lol "THE WORD FOR JUMP ON THE TABLE IS OVER NOT ON! DO NOT MAKE THAT MISTAKE AGAIN!!" and Aussies tend to be more forgiving of fumbling handlers lol probably because yea.. most of the time, it's a big game
- How they deal with handler stress. Border collies tend to mirror anxiety/sadness/stress, they bond in a very close way and feel the same way their handlers do. Aussies tend to try to cheer you up and make you laugh.
- Tails. Aussies typically don't have them so they can't knock over things on coffee tables. Border collies have tails but it's easier to tell their feelings by how they carry them.
Depends on what you think is "easy" lol
- Aloofness towards strangers. Both breeds are considered aloof.. but from what I've gathered.. aussies stray on the side of more friendly. Give them a minute and they will give you a butt wiggle, say hello and then go right back to their person. Border collies will just blow you off all together until they trust you..and even then lol
-Affection. Border collies tend to be more mannerly in their affections. They show love by working with you, being around you, cuddles. It's a quiet affair at times.
Aussies cuddle, butt wiggle, body slam, hop, bounce, bark.. OMG HI I LOVE YOU SO MUCH!!! HIII!!! HIIII!!!
I've seen how border collies play at the park vs. aussie and there are some OBVIOUS differences. Lots of body slamming on the aussie hand of things lol
I like affection that comes with wiggles and body slams and weird noises.
Some people find that..difficult.
So yea, it's not that one is 'easier' IMO.. just depends on what you think is easy.