SeanT - well...IPB's can get indexed, but I've only ever seen this done in part, and don't know what work arounds may be available. It just means it'll be harder to net lots of small traffic terms if the indexing isn't great.
But it is a nice looking site. I'd say presentation is going to be your stronger point here. If people like that then it'll be easier to get the backlinks that will make all the difference.
Hope I didn;t worry you too much, but you did ask about weaknesses.
Concentrate on your strengths and you should do fine, though.