Don't underestimate manufacturers. Ever. Don't underestimate Microsoft's competitiveness. Ever.
Why do you believe that the Windows Phone 7 hasn't made an impact on consumers out of curiosity?
I do not underestimate anything. But none of the major manufacturers has any proven record of selling tablets and for a good reason. They are in the hardware business, they are not in the content provision business. They are neither Apple nor Amazon. They can only appeal to businesses which are the major purchasers of their products. Thus, their tablets are and will be targeted to businesses (if they need them), not consumers. Neither Lenovo, Dell or HP have any ecosystem to support consumer-oriented tablets. Nor can they offer tablets at $200 because they have no way of making money through content. Dell had a 7'' inch tablet out there for quite some time until it finally killed for poor sales. Amazon, on the other hand, sold untold millions of Kindle Fires. At $199, they are an impulse buy. At over $500, it gets to be a different proposition. At that level, nothing beats the iPad.
Why do you even ask about the impact of Windows Phone 7 with the consumers. It even trails Symbian for market share!!!! Even in the US, it has a 5% market share and it is actually declining. Despite "Mango", it had an underwhelming performance during the holidays. So, despite lots of advertising, it has been a commercial flop. None of the WP phones even offer LTE speeds nor do they support multi-core processors. WP may get to be competitive at some time, but it would not be any time soon.
In November, I had to get a new phone. I examined very carefully WP7.5 and Android phones and decided to buy an Android (The Galaxy SII Skyrocket). In fact, I believe that you would have reached the same decision. If you are presented with a phone with very limited customization capability, no expandability, no access to the file system versus one that has all these and much more (almost infinite customization capability, additional storage, true multitasking, LTE speeds, dual-core processor, etc, etc) why pick up the first? It makes no sense. WP7 is not Windows, it is a new and very closed OS.