I cannot comment on the Guillemot, but I have paddled the Coho and Capella.

Coho: Pretty, fast, neutral, strong tracking, stable, resists weathercockiong very well, large volume, excellent touring boat. Cockpit opening is too large for my tastes, making it difficult to install proper knee braces, although Pygmy now has a knee brace kit which is supposed to be an improvement. Does not turn very quickly unless you really lay it over which is difficult unless you have good knee braces.

Capella: Heavier (Plastic), excellent fit for my 5'-11" 200 lb. frame, good hatches, OK cruising speed, surprisingly strong initial stability for a 22" boat. Lower volume than Coho. Tracks very poorly unless skeg is down. This is the most significant difference. If you are a cruiser, the Coho is better option, but if you want to turn fast, well with the skeg up the Capella almost spins. This makes it great for rock gardens. More appropriate for play situations.

: I have not paddled either boat so take my comparison below for what its
: worth.