I would do the Crimson which is reported to have more aggressive bass and punch with two poles. The Clearaudio Titanium is another cartridge I would like to try.
@mijostyn That was my thought on the two going in, before hearing them. I liked the traditional 2-pole architecture of Crimson, and the extra output. My Crimson is 0.75 and Colibri is 0.38.
As it turns out, the Colibri is punchier than expected, with awesome macro-dynamics, and I wouldn't consider that a critical advantage to Crimson. That said, the Crimson is much easier to setup and start enjoying. There's still a touch of sibilance on this Colibri - not sure when that goes away on its own (when fully broken in) or I need to keep tweaking. Sibilance isn't a hot trigger for me and it's not too bad now anyways (was awful earlier in break in). No sibilance issues with Crimson.
The Crimson is a little smoother and warmer overall. Still not "warm". Midrange isn't "fat" like some Japanese carts, nor dry like some Ortofons. Definitely a great choice IMO. Colibri a little faster and more detailed.
The matching is different due to the output levels. So far I like Crimson best into my EAR MC-4 SUT, and Colibri best right into the JFET MC stage of Hagerman Trumpet Reference (~ 180 ohms load). The Crimson's output level is somewhat deceiving; it's not as high as I expected for 0.75mV. The AirTight PC-7 rated at 0.6mV is louder in practice. I think Shelters at 0.5mV are a tad louder too. The Crimson is more like what I'd expect for 0.45 - 0.5mV. Colibri's 0.38 isn't far off from what I expected there. Crimson is louder, but certainly not by 6dB.