I also use an XS with the OT, and I really like it. I often sample the XS and layer it with itself. The big weakness of the XS is its LFO (narrow range of rate, rate isn’t modulatable, not many ways to modulate LFO depth), so to get interesting modulation, I often crank down oscillator B into the LF range. This leaves only oscillator A as a sound source, but that plus the multi-mode filter makes it easy to create layers that fit together in a sampler (OT or a softsampler).
It’s also just so damn good at percussion, probably because of the nice mixer saturation and fast envelopes.