In regards to your full text request. The publisher has the option what to syndicate, truncated or full.

What you are asking them to do is have a crawler go to the site and pull the full text whenever they feel they are being served truncated.

Not only does that go against the nature of RSS, but would be costly for them.

What app do you pay for that does this? Is it even using RSS?

Quite a few apps provide this. One is called Newsify.

I don’t know that it goes against the nature of RSS. I kind of feel that providing only a title of the article and a link goes against the spirit. But nature and spirit are different.

It really depends on how it's done. Some sites, like Wired, tend to give you a short, one or two sentence abstract of the article so you get the general gist. If it piques your interest you can click through for the real meat. I'm okay with this. They have a paywall after you read more than some amount per month, and I believe they have a special subscriber RSS feed with full text. So this solution seems like a good way to both respect my time (by only inducing me to click into stories I want to read) and maintain the value of their subscription.

Other sites, like Slate, are more annoying. They write headlines and opening paragraphs that are "Slate-pitches" that are trying to goad you into clicking. These I have no patience for and eventually unsubscribe from after my fourth or fifth click-through to a thoroughly boring article.

Unfortunately newsify is ios only

Feedly is the only one I've found where I can sync my feed between browsers and my phone. Every other service seems to be stuck in one area or another. It's really quite annoying. I need a feed reader that works on every device that I read things on.

Given that one of the blogs I follow charges for access to a full-text RSS feed, my guess is that some sites might be upset with them if they did that.

Ah yes, one of the resources I follow is a newspaper where I pay for the news weekly (FT). I only get the title and a link.

Or pretty excited depending on how they charge.

How well do these handle mathjax and the like?