I have 7 Moultries, mostly the I40 and one I60. They add did great for about 16 months and every one of them has experienced LCD display problems. The cost to repair would be $40 per unit plus shipping as they are out of warranty. They all worked great and literally took thousands of pics each, but all have developed problems.
The Moultries had a medium length delay between sensing movement and taking the image. The timing turned out to be pretty good most of the time. I have a Stealth cam (don't remember which one) and it has a LONG delay. This seems typical for most Stealth cams. That makes the camera really only good for locations where the animals have to stop, such as at feeders, water hole, etc. Otherwise the animals have too much time to cruise through the image field before the camera takes a picture. Cameras that are too fast runs the risk of taking pictures just as the animal enters the image field and you end up with a lot of heads and half bodies.
I went with infrared cameras for night shots because there is no flash to spook the animals. If you have skiddish animals, the flash will bother them. Some will definitely take notice of the dull red glow if the infrared cameras as well, but are not nearly as likely to be startled by it.
In general, more pixels is better than less. Depending on where you set the camera and what you want to catch. A fast reaction time is much better if you are hoping to catch birds flying through or quick moving animals along a trail. Slow/long reactions are better for feeders. So I like the mid range stuff that covers both realms pretty well.
With IR cameras, the "flash" can be awfully limited. My Stealth cam projects a circle of light such that the corners of the image are dark, but it projects the light further than my Moultrie cams. The Moultries IR flash is more like a flood light and the whole image is illumated, but only good for about 40-50 feet.
In the past, I have found very good information at these sites...
http://trailcameras.net/
http://www.chasingame.com/
http://www.trailcampro.com/reviews.aspx
http://www.whitetaildeer-management-and-hunting.com/digital-trail-camera-reviews.html
Note that not all of these sites are completely free of biases and may be affiliated with selling the products being reviewed. Some of the information may be out of date as well. In general, don't count on the prices listed as necessarily being what you will end up paying. Most list the list price which often turns out to be more than you will end up paying, especially since cameras often go on sale.
Things to really consider are trigger times (aka delays), flash (type, amount, distance, coverage), battery types used, and features such as whether or not it has an aiming laser (very helpful but not absolutely necessary), information stamps (time, date, moon phase, temperature, camera number/designation/name) and how many shots can be taken for a given trigger. For example, the Moultries can take a picture or sequence of pictures at intervals of as little as one minute up to 30 or 45 as I recall, but may take 1-3 pictures for each trigger event. I have my cams set to take 3 pics at intervals of 1 or 2 minutes (depending on where the cam is setup). The multi-pic setting on the Moultrie will take those 3 images about 13 seconds apart. On the Stealth cam, I believe it would take up to 5 images and they were 3 seconds apart. You may want to take short videos. Cool. These eat up memory very quickly and usually aren't all that amazing. You will have silent movies unless you get a camera with a microphone. I don't see much need for movies or a mic and so I don't use the movie setting and my cameras don't have mics.
