I think it depends if you're looking at it as some kind of investment/heirloom piece or not. Smaller diamonds wouldn't have such good resale value as the equivalent amount in one stone, and as someone said you might not get that much light or sparkle off that size. On the other hand, if you love the design, want them and can afford them, go for it. Resale value isn't everything, if you intend keeping them forever then why should that stop you. Not being the ideal size, cut etc that a jeweller might prefer doesn't mean they might not look lovely and make you feel great.