I recently purchased the Canon 50mm f/1.8 lenses after reading many reviews of the two f/1.4 lenses you mentioned and the f/1.8 on Amazon and several other sites, including Canon's own site. There were numerous complaints of focusing issues with all three lens. There were also complaints of poor build quality (autofocus failing after a few month or a year) with both Canon lens. I finally gave up in frustration and bought the f/1.8 lens for $100. I decided that if I was risking a problem with any of the three lenses, I rather waste $100 than $400+. I've had the lens for a few weeks, and no major problems so far, although the autofocus may be off a tiny bit. If you want a 50mm lenses with no bad reviews, and are willing to spend about $1,000 more, buy the Canon f/1.2. JMHO!

I was trying to focus on the Queen