I'm something of a beginner in both Asymptote and PGF/TikZ, but I'm a bit better at Asymptote, and so I generally find Asymptote easier to use. However, I find Bezier curves a bit easier to control with TikZ.
Of course, the obvious (and best) solution is to just get better at one/both of them. I'm not really asking for recommendations for either Asymptote or TikZ (although they're always welcome!).
What I was really wondering was this: In general, is it considered bad practice to use both Asymptote and TikZ in the same document? Or is it acceptable? For example, I can imagine that even for an advanced user of both, there are relative strengths to each, which might make it desirable to use both languages.