Microsoft's Bing and Palm's Pre would work as good incremental improvements, but they are not good enough to challenge the established industry leaders, Google and Apple respectively. Challengers need to offer a "10X-differentiator" feature to change people's habits. Here's a couple of quotes for my records:

WSJ (via BusinessInsider):

The Yahoo CEO also dismissed Microsoft's newly revamped search engine, dubbed Bing, as an improvement that will spur temporary interest among users, but do little to alter their long-term search habits.

"It's interesting but not over-the-top interesting," she said. "People will keep the same habits."

CNet review:

Palm has really made a solid and smart platform and one that doesn't just match the capabilities of its competitors but offers something more in its multitasking and personal information management capabilities. Palm might not have completely knocked it out of the park with the Palm Pre, but at least it's back in the game, and we look forward to more WebOS devices the future.