ShopTalk: Swing Speed Analyzer

[Nineback]

I am looking for swing speed measuring device.  I have noticed that there are some that range in price from $60 for a very basic unit to $400 for an advanced unit that connects to a computer.  I see that Bel sells a basic unit for around $100 but I seem to recall hearing that it isn't very good.   Any suggestions on a good basic unit and a good advanced unit?   Thanks,   Tom