I don't think "better" matters in current valuations. Nor does comparison to competitors really matter too much to the valuation - what matters are the revenue streams and potential for future earnings. So the number of current clients, and prospective clients, seems more relevant.
> How easy will it be for Lyft to develop its own payment technology?
Depends what you mean here. Any of these large companies are going to have their own merchant accounts (or should) processing payments for them. Stripe needs to either 1) take out the bottom of the market, which is what I thought they are competitors were doing and/or 2) come in cheaper and/or more convenient than maintaining your own payment services and such, which I think they do in some cases.