DS 3rd party support mercilessly kills the 3DS library in public and gets away with it before court. If you bought DS for Nintendo, you did it wrong.
i buy every nintendo console for nintendo games primarily
so the first party content not being there on the ds really hurt that platform for me
and I actually tried most of the acclaimed third party games on ds, almost none of them stuck with me. so even with the third party support i'd say 3ds>ds