I’ve had a swift and now own an El-Mariachi.
Both are decidely old-skool XC/Trail bikes, just 29ers, they’re not long/slack/low or anything like that.
The Swift is the more flexible/comfortable/’steel is real’ of the two by quite a margin, especialy the fork, the Chromoto is much much stiffer than the Singular fork (not in a bad twisting way, in a more comfortable way), the Salsa is much more direct and stiff.
V-brakes actualy require a stiffer frame than disk’s as they need the stays braced together and stiff to stop them splaying appart, disk brakes mean they can be less stiff as they don’t have to resist those forces. Whereas with disks all that force is contained in the calliper.