Most other DAW's have caught up with their piano roll implementation but I still like FL's the most. I think what makes it unique is its toolset -- as in, the toolbar up top -- as its modal editing workflow lets you add, delete, and then transform notes incredibly quickly. Most of these modes have a shortcut to get to them, and its easy to flip between them. It even has a chord option, which functions much in the same way as that hook tool. Other DAWs take a modal approach but in many cases they complicate their implementation.
It's also worth noting that FL is pattern-based, whereas most DAWs are not. ("Pattern-based" means you generally write music phrases/patterns and repeat them throughout the track, this is helpful for electronic dance music.) A repeating bassline pattern in FL is more akin to a series of symlinks back to the original file, whereas in Cubase and Logic, each of these repeats would be copies (unless you specify otherwise, but I found the implementation convoluted and troublesome.)
Most of the other DAWs I've worked with are much more fiddly and require messing with technical details and audio routing to get a good result. FL also requires this, but again the implementation is seamless, has sensible defaults, and stays out of your way until you need to mess with it. (In the middle of a good flow I have very little patience for routing.) I do not find this to be the case with Live, Cubase, or especially Logic... I put in an effort to learn each of these at some point and ultimately left to return to FL.
I've noticed DAWs tend to optimize around performances (Live), MIDI orchestration (Cubase, Logic), recording (ProTools, Reaper) or 'in-the-box' production (FL). All of the above have tools for composing by mouse but FL's workflow is optimized for this specific use-case.
