Interesting comparison. I owned the Model 1's (and auditioned the Signatures before deciding to buy the Merlin TSM-M's). My experience with the De Capo is limited to a single 30 minute listening session, so take that for what it's worth (though I have quite perceptive ears and a photographic memory).
Totem's cannot be run successfully with less than 50 watts tube power, and double that for solid state. Do not believe otherwise. They frankly do not reach their potential until coupled with a high power, high current amp, preferably solid state. Not very sensitive, and very demanding (sounds like an old girlfriend I dumped

). Nevertheless, I still enjoyed the year I spent running the Totems on a 35 wpc integrated tube amp, since I listened at night at very moderate levels and used a REL Strata 3 to round out the bottom. But you would NEVER use these with SET's like you can with the De Capo. And when I turned up the volume to rock out, the sound quickly compressed and became bright. Also, they need to breath, and 3-4 feet from the rear is about right; whereas the De Capo seems to do well against the rear wall during my audition.
The Totem still images with pinpoint accuracy, more than my Merlins and seemingly more than the De Capo's did in my audition. However, like nearly all speakers with metal dome tweeters, over time they can fatigue the ear. Bright recordings seem even more so, whereas the De Capo's had the same type of extended highs but are probably less fatiguing over time. (The Merlins have NO fatigue, sound wonderfully natural, but may lack the ultimate extension in the highs).
Great soundstage and depth for both; the Totem's especially disappear nicely. Both have more bass than they have the right to, being so tiny and all. Both the De Capo and the Totem are ported, which lends better bass extension and more efficiency, but IMHO does not provide the level of detail and articulation that you get from a sealed box (this goes for subs too, IMHO). You cannot biwire the Model 1 unless you find a version with biwire terminals, but you can biwire the Signature (and methinks the De Capo too).
Unless you are starting from scratch with your amp, I would not consider the two speakers as competitors. If you have less than 100 watts (or 30-60 watts of tube power or even a flea powered SET amp), I could not recommend the Totem as a long term keeper unless you upgrade your amp. Merlins, B&W CDM1's, Revel M20 (both power hungry too but not as bad) or something like a horn speaker or a Lowther based speaker may be more up your alley to compare with the DeCapo (the Merlins are easy to drive, but probably not SET compatible). A better comparison with the Totem would be Dynaudio 1.3 Contours, B&W N805's, and Thiel CS 1.6's, which like power/current and which are small and do different things well. I have also heard that the Tyler Minimonitors are worth a listen.