Easy to follow, allows freedom of choice

I have been following the GI diet and found it very effective and rarely feel hungry. Signed up for 6 months when on offer so works out reasonable cost per week. I frequently change the meals and find it quite easy to change whole meals or single items for accuracy. Also easy to input your own foods to use if not already listed.
I find keeping track through the day makes it easier to stay on track than leaving it for a few days and then inputting. You can change your final meal to keep carbs/protein/fat levels within the daily limits.
Downside - I have used Sainsburys diets before and you could input your exercise and create your own recipes without paying extra. It would be nice to be able to log my exercise alongside my food choices. I don't think it's worth the extra cost to be able to do this.