I'm probably going to be going to film a trade show, and it is NOISY as hell. I figure the best way to record the presentation would be to set up a lav on the speaker. However, with all the electronics at the trade show, I'm sure using a wireless system would have tons of interference.

I have a Zoom H4, but I was thinking about getting a Zoom H2 or Zoom H1 to be used as a field recorder - I can sync video & audio in post. Since I'm not really worried about the audio quality of the built-in mics, can I go cheaper, say a Tascam, or something like that?

What's the final use for the video? Theatrical release? Training video? Home entertainment?

It's hard to advise about equipment without knowing what quality level you need.

Final use will be in corporate YouTube video for a tech startup.