MfP is awesome! Lots of support from here!

I just switched over to myfitnesspal from sparks mainly because the database of food is better. However, the one caveat that I would say for all of the sites is just to ignore what they think your goal calories should be. IMHO, everyone has to determine what calorie level works best for them. All of the sites offer good means of tracking your calorie and carb (for people like me who need to track both) for the day. Just depends on which you like better for the "extras."

I totally stress over this--how many calories should I be eating? I'm seeing a dietitian next week, but I don't really have any reason to believe any number anyone says anymore, since there isn't any consensus anywhere.

In this one area, my logic isn't strong enough to say "as long as you're losing weight, you're doing fine." and "every piece of data you put in there is an estimate--this is not exact"

This may be a stupid question, but if I am friends with someone on MFP, can I see their food diary?

If they don't keep it private, you can.