Is it really easier to develop in HTML5?? I haven't looked into it lately, but it was a nightmare last time I checked. Compatibility problems, massively differe

Is it really easier to develop in HTML5?? I haven't looked into it lately, but it was a nightmare last time I checked. Compatibility problems, massively different performance across browsers (so you have to go lowest common denominator), every guy and his dog coming with his own layer of abstraction and libraries to make for deficiencies that simply don't exist in AS3... I'd be interested in looking into it again if you can truly achieve the level of compatibility, penetration and dependability (performance-wise) that you can achieve with flash. Any pointers will be appreciated.