This is the first time I've released a game that had a free version available.
Looking at the stats after 2 days running I have hit 180 downloads and then 150 downloads for yesterday. I've never known what kinda volume of potential interested people in a single project per day looked like....now I know this will die down but I also noticed a spike in sales that looks like it helped having the free version to test out first.
Also its nice to have a free version to hear all the complaints they may have instantly....and fix and update the downloads.
when you have a free version you get allot more feedback allot faster then on a paid version....this gives you time to fix any bugs and patch it up again for both releases.
I highly recommend when releasing a new game to actually release 2 versions at the same time. Make note that there is a free version to try on the buy one... and vice versa in your game description.
I will need to go back and release a free hockey game (limited version) to see what happens to my ice brawler sales.... im very curious now... also it doesn't hurt to mention your other apps available in your descriptions.
edit: im also going to go back and fix up my ants game and re release with a free /paid version to see what happens with that one.