Never used them but you should look into the PLX models. I don't have one personally but my friend does. They have an awesome customer support line, and definitely know what they are talking about.
ebay,$360 shipped with the LCD display. Its pretty awesome to be able to see the MAF voltage in realtime along with the AFR/Lambda. I also love the one button press on the side to see peak #'s.
You can get the non display model for as low as $250, just have to use a laptop to get the data off. I recommend the display fully. Its a very trick part.