For me the Chipex gives a neater result, as I'm a bit clumsy and not the most proficient working with paint and a small brush or pin. Thinking about it some more, you could probably achieve a deeper chip coverage with Chipex by using multiple coats, but you would probably need to wait a few hours between coats for the paint to dry sufficiently.
Edit: Alternatively, you could probably get a paint shop or repairer to make up a small tin/bottle of touch up paint, as long as you have the paint code. If you have steady hands (I don't - I have a tremor) using a small craft brush would probably give the best result.