I've always preferred lizardfolk to dragonborn personally, but it's a relatively mild preference and I generally have no objection to dragonborn as an option. I guess dragonborn as a concept read to me as more the opportunity to play a PC that looks like a dragon (an explicit reason to play one according to 4e) than anything deeper, whereas lizardfolk to me have that "lizard mannerisms but human intelligence" thing going for them.
Honestly, I don't think any particular heritage is necessary for play in general, except human (unless the setting concept specifically excludes them, I really like a human touchstone in the mix to provide contrast).