Right now, there are two pretty cool online Macro coaches that I've used. The first one is Avatar Nutrition. They are currently ramping up their version 2.0 (sign up to be an insider here and get two free weeks when it launches). I've been using Avatar since about March and have had some great success on it. The good about Avatar - an amazing support staff, it's relatively inexpensive ($10/month), you get weekly adjustments, high/low days, it has a reverse diet function, and more. They don't have an app yet, but should in about three weeks, as far as I know. I believe it will be both for the iPhone and Androids, which is welcome news.
The macro calculator for Avatar uses lean body mass for its protein calculation. It has a slider for carbs and fats so you can easily trade between the two. Right now, there is integration with My Macros Plus that allows you to easily see your daily macros in an app, but I'm hoping the new app directly from Avatar will be better. There are weekly weigh-ins with a multitude of goals.
The only bad things about Avatar are things that appear to be getting fixed soon. The website itself is very old. The articles are all pretty old and nothing's been updated for a long time. Again, this is all going to change on January 7th.
I've been trying FitGenie for a couple of weeks as well, just to see if I liked it any better. I do like it, but I'm going to stick with Avatar. FitGenie has a Premium Subscription option, but the base is free. It adjusts your macros weekly as well. It gave me more protein than Avatar recommended and appeared to base it on 1 gram per pound of bodyweight. You can also plug in your macros manually. The app itself is very nice, and they have a really cool meal planning option with the Premium service. One thing I haven't discovered yet is an easy way to pick high and low days like you can in Avatar. That's something I really like - I often know I'll be eating out, having a big workout day, etc., and it's easier for me to keep on my weekly macros by having a high day and a couple of low days.
I don't think you can go wrong with either Avatar Nutrition or FitGenie. If you don't want to pay anything, FitGenie is obviously the way to go. I like Avatar's customization a little better, and at $10/month, I think it's worth it.