For me, it's biggest strengths in comparison to other DAWs are:
- step sequencing using keyboard (this one is huge and the biggest reason I use a tracker - nowhere else I can lay down ideas as fast as in this environment)
- editing and navigating patterns using keyboard
- powerful, easy and quick to use sample editor/sampler
- integrated slicer: although missing some features (especially "pitch mode" - playing sample from current position (not just start) or selected slice through the midi keyboard), it is still one of the best and quickest I've ever used
- very stable audio engine with great and stable support for VST plugins
- cool tracker commands (although I use them somewhat less than I used to, especially before it had a slicer)
- usable on single monitor setup and smaller (laptop) screens (although version 3 is a step back in this area, with 3.1 being a step in the right direction, but still not as good as 2.8)
Weaknesses for me are:
- no piano roll (I know it's a tracker and most of the time I prefer tracker interface, but for some uses - especially for chords or longer melodies - piano roll would be nice to have)
- no linear mode sequencer or at least tracks that can expand through multiple patterns: e.g. when having long melody, you can only make a very long pattern, which means copy&paste the content of other tracks through it... or when making a song with lots of variety, the number of patterns just goes to the sky, because every little variation demands a new pattern.
There seems to be quite a demand for audio tracks, but I don't miss them that much, actually autoseek feature quite filled the gap for me in this area. I use Logic for this and I doubt Renoise could come close to the features I need in this area any time soon. And it would surely raise the price and make it more complicated and clumsy for sequencing.