Sony HX100V is Great
Bought the Canon SX30 last June, thought it was decent, but returned it in a week to buy the Sony HX100v. The Sony was new to U.S. market, but had great Amazon reviews...but NO professional website reviews. [The Canon was already highly regarded, with many reviews.]
Despite the uncertainty over lack of pro reviews (at the time), I took a gamble and have been thrilled ever since. It has since had lots of professional reviews and MANY more Amazon reviews (originally 25, but now 135), as well as great popularity on one particular camera forum (dpreview.com). For ME, the Sony features have been just wonderful. It was a long learning curve to get accustomed to all it can do...and I expect I will have to re-learn a lot, when I start using it again this Spring.
Rather than me trying to summarize what is so great about the Sony, I recommend that you read the Amazon reviews for BOTH cameras (the new Canon SX40, as well as the HX100V...and the HX200 is supposedly close to market). There are tons of pro reviews, which can be found via simple Google searches for each camera.
Just one special bragging point: The Sony 30x Zoom is awesome and works great, without any problems in focus stability or use. I frequently use the digital zoom to reach out to 60x and beyond, and think the pictures are still "good enough."
Both the SX40 (new last Fall) and HX100V are very well respected. It all depends on YOU reading as much as you can about each, and deciding which factors are most important to you.
NOTE: I bought an aftermarket battery charger and 2 batteries for the Sony (which has excellent lithion battery life), and expect to continue enjoying it for several years...until the "Next Best and Greatest" comes along.