If you are going to run MicroISV or just launch any startup - what you are going to stress on your forces -- Execution or Innovation? Personally, I believe that Innovation nowadays is pretty much hard to achieve, and usually hard to recognise and respect by customers. If you'll succeed - spot of proven leader will be backing you up. But then Execution will mean everything in this business. Frankly speaking, Execution is #1 for me. Many startups became succesfull by bringing old/working ideas, but making them fresh looking or nice advertised.
From the top of my head - examples: YouTube and Google Video. Did YouTube bring better data storage idea? No. Innovative idea? No. They brought something which is easier and nice looking, comparing even to the giant Google. User experience was better. At the same time I should mention 39signals - the company which builds nice applications, not innovative or very-high-tech, but just usable. And they execute the business better.