Late is a relative term, just because they weren't the first does not mean they can't succeed. I'm sure you can think of plenty of examples for products that were not first but succeeded or even overshadowed their counterparts. It's all about the execution.
Easiest example would be facebook and google who really weren't that innovative. This seems to come at the end of this pair, path craze.
Fair enough - I'm trying out the app now and I'll reserve further judgement until I've thoroughly tested it.