I agree with you. If the product is as flaky as you suggest, then by all means get them together for a concept discussion with some slides mocking up the functi

I agree with you. If the product is as flaky as you suggest, then by all means get them together for a concept discussion with some slides mocking up the functionality, but when they see the product, they'll need to be very understanding to be impressed by a half-baked demo, in my opinion. 'this is x' is more powerful than 'this will be x', because 'will' really means 'might' and introduces doubt, whereas 'is' is concrete and undeniable. You know that adding pretty logos is simple stuff, and that the real challenge is in integrating the data feed quickly enough, but your customer very often just assumes that the functionality will be there, and only worries about the flashy cruft. Get the flashy cruft right! I think it's easier to sell a product that looks great but does nothing than a product which does loads but looks terrible.