Old battery was dead - after two years of use it held charge very erratically and for a short time.
Sweet as a nut. Followed the perfect picture tutorial on iFixIt.com - my first time opening an iPhone - and it took probably about 30mns altogether. I didn't time it, but it was simple and easy to do. The spudger and suction cup worked as advertised, perfectly adequate for the job.
The only thing I could wish for is that there was some kind of extended life battery - the new one sure is better, but still I don't get much more than one day and night on it with average use. My old Nokia lasted over 3 days with the same use, of course it wasn't an iPhone, but still..