I've stuck with version 9 for about 7 years. I remember there was one particular function for sampling that they had removed in that upgrade, but otherwise, IMO it is the pinnacle of the "old" design.

Before I get too deep on this rant, let me just say that any solutions to these issues are more than welcome. I'd like to believe that I'm wrong about my experiences with trying to get adjusted to the newer designs -- I'd enjoy nothing more than to use Fruity Loops to its full potential.

When I've tried 10 - 12, they all seemed to handle memory and processing poorly. I've taken into account that some of the time spent using them was on a fairly outdated computer. Granted, more memory can be dedicated to FL in the newer ones with bridged plugins and 64-bit support, but even with that, they just never seem to allocate resources as efficiently as 9 does. Even with a better machine, it's still a noteworthy factor.

Then there's the dreaded interface. I know, I know... it just takes practice to get used to it, and in due time I'd eventually find the bubbly graphics more appealing. If it wasn't for everything else, this probably wouldn't even be worth mentioning.

The one thing that stood out the most to me was how newer versions would automatically double a note on the piano roll if I held the mouse down for more than a moment. That's one habit I've tried to change in the interest of moving to a newer version, but end up just getting fed up when I hold a note, trying to visualize whether that is the pitch I have in mind, and FL deliberately doubles the note. It seems like a minor thing but when it happens so frequently, it gets quite frustrating to lose the momentum behind an idea altogether due to being preoccupied with deleting\moving notes that shouldn't be there in the first place.

I'm also not fond of the new(er) playlist design but I could probably get familiar with it, if that was the only gripe I had. I'd say that goes for all the other little differences as well. Many options still function the same as before, but collectively, everything adds up to making just enough of a difference for the extra memory management to not even be worth it.

tl;dr My workflow is the most efficient with Fruity Loops 9. If I could manage to get around a few select obstacles, I'd love to use the newer versions due to their lack of limitations with memory.