I have included a parsing routine in the plugin that looks for "alternate" in the head of the authors page, it doesn't rely on that to find the feed location first because not all hosting provides the ability to do 'curl' commands or open remote files with 'file' and 'fopen' and I wanted to have the most compatible way done first, the parsing routine gets called if no default feed location is used.
also, if it is an own domain blog it will by default, try to look in /feed/ first and then /?feed=rss next, if there is an alternate link in the head then the second option should get to it.
it is quicker to see if it is a blogspot blog by examining the author url because then no parsing is needed and the internal wordpress rss.php function will be able to read that with no problems, the code is very small and is executed at server side so it's more efficient to check the string than to open a file.
I have a new version running as a test on my blog and it's having great success with removing nofollow and also parsing blogspot blogs hosted on their own domain which I only found out because of the feedback I get from people that use it and people that code like you. I hope to get commentluv working on as many, and parsing as many blogs as possible so I appreciate your input.
there are improvements to the cache of the feeds too and an ability to make it show the debug info to make tracking down of errant blogs easier..
I hope you get a chance to use the new version when it's released soon and spread the luv ;-)
Andy Bailey of fiddyp.co.uk