If I started with flippy caps I probably would not have a problem with them. Generally, fixing something that does not have a problem (regular screw-on caps) will annoy many, myself included. They seem to work ok for the most part, but I do now have a little pile of broken ones. Moving parts break more than non-moving ones, unless the non-moving ones were flawed (which they weren't, in this case). In my case, the flippy's do the job, but the screw on caps just didn't need an upgrade, simple as that. Sometimes upgrades are good because they address problems, other times they are just a tactic to get you to buy the next item they slap on the shelf.
They might actually be SLIGHTLY more convenient. There's no doubt in my mind that there is a cost in reliability, though. I prefer the screw-on cap as part of an overall "less is more" philosophy regarding chainsaws. The KISS principle (keep it simple, stupid) reigns supreme when reliability is critical.
The tool-less tensioner thing seems like a pretty good idea to me, but it would have to work as well as the scrench method. What they have done so far has been pretty rinky-dink.