NerdSeq is likely the deepest and most versatile sequencer available for the money and HP (excluding using a DAW with stuff like the FH-2). You have a highly manipulable sequencing environment, a very capable little sampler, and (especially with the LaunchPad integration) an extremely powerful performance tool with its Ableton-style pattern launching. The UI is extremely well thought out, and even though you can go extremely deep with it, I never feel like I'm diving deep into menus or forced to remember too many esoteric input combinations. Just about anything I can think of, I can find a way to accomplish with the NerdSeq, often without involving any other modules.
That said: I occasionally find myself considering selling it. It's not due to any fault of the sequencer itself, but rather that because it's so deep, concessions have to be made in regards to workflow. I'm an avid tracker user, with Renoise as my DAW of choice, but it can be extremely frustrating having to set up menu options and perform a bunch of inputs to accomplish something I could have done in a couple button presses or knob turns on another sequencer. The LaunchPad integration does help immensely with this, but it is still a persistent source of frustration.
My issues with the NerdSeq largely stem from my philosophy around modular. I prefer to treat my patches less as realization of a cohesive musical idea, but rather a meditative exploration that may or may not grow into something more. I hold on to the NerdSeq in hopes firmware updates, expanders, and creative patching solutions will offer new promise, but I do seriously wonder if I'd be happier with a Metron and a couple Volteras. If you're the kind of person with a really thoughtful and prescriptive approach to composition, I think you'd be hard pressed to find a better tool than the NerdSeq.