I really can't understand the point of Adsense - does your website get lots of visitors? I also can't understand why you want to include possible competitior sites on your website - there is a competitor filter, and contextual filter, but you've got to keep an eye on it - you never know when someone will start using a pay-per-click option and appear in the results.
But the biggest thing is I tend to look at sites with Google Ads on them and think they're trying to make money however they can, they're not concentrating on their business, they're not serious about their main business. That is totally just my perception, but I take sites without Google Ads more seriously than those with. I'm sure others are either more accepting, ignore ads better than I do, or more gullible and think since it is on your site you are associated with them so they must be good.
related idea - an old pay-per-click thread..... http://www.massageplanet.com/forum/viewtopic.php?t=1416