I have tried both BriteAds as well as BlogAds. Both allow advertisers to purchase ad space on your site for fixed duration. You can select the duration and payment. After several months of trial I now have a clear winner (for my blogs).

Note: BriteAds have other ad models too. For this review I will consider only their duration based ads.

BriteAds
I used BriteAds on both Simple Thoughts blog and Computer Jobs blog.
Positives:
They provide a pool of CPC network ads which can be used while waiting for an advertiser to choose your site.

They accept sites irrespective of their daily page impressions etc.

Negatives:
Initially BriteAds had not so clean network ads. So I chose not to use them. Later they had better network ads so I enabled them for sometime before I realized that neither impressions nor clicks were properly accounted. In short I haven't benefitted from them in any way. Also the ads are not targeted.

Few offers which came from their didn't cater to my sense of decency. So I was forced to reject them.

They introduced interstitial ads with low pay rate which I don't think will fly. Personally I am very much against interstitial ads. So I rejected all offer which came.

BlogAds
Positives:
There are lots of positives. Their ads have a personal touch, colorful and are mostly very interesting.

Their pool of advertisers are normally companies you wouldn't mind advertising on your site. Take a look on my right sidebar to see some of the advertisers.

You compete with mainstream bloggers without having to worry about sploggers (more later).

They have a clear upfront policy about their cut from the revenue which I think is fair and should be followed by all.

They appear to be gaining momentum while BriteAds appear to be losing some of it.

Overall I am happy with them.

Negatives:
Initially their ads used to jump around the page, which has been subsequently fixed.

They do not have a open door policy. Blogads is now invitation only. To participate in Blogads, you need to be sponsored by a blogger in the network. If you don't know a sponsor, write sellers@blogads.com and they will notify you when a sponsor appears in your niche. On the positive side it ensures we don't have to compete with sploggers.

Winner
BlogAds is a clear winner by all counts. I consider it as a wonderful monetization means for amateur and business bloggers.

Your feedback on these products are welcome.