Good question!
I'm not sure how you currently add fillups to fuelly but one advantage is being able to add fillups via text message. Not everyone has a data package for their phones so we wanted to come up with a way for them to be able to remotely add fillups. Also you receive a text back with the MPG for that trip. So you don't have to wait until you’re around a computer to see your MPG for that trip.
We also have a full mobile site. Basically anything you can do on our main site you can do from your mobile phone. Fuelly's mobile site is seriously lacking in this area. We just released our android app last month to make it easy for Google phone users. Just search the app market for "fuel mileage", our app is "The Fuel Mileage Tracker". We are just about ready to launch our BlackBerry app as well.
Also when adding your vehicles you have the opportunity to add a list of modifications. So others can see if your vehicle is completely stock opposed to one that isn't.
In regards to searching for other vehicles, I like to think our method/options are more in line with how the user would want to search. We have 2 options. First you can drill down on Make, model then vehicle. Our 2nd method allows you to search for a keyword. So rather than have to search through a page with tons of makes and manufactures you can simple to a "keyword" search and it will return every make/model/vehicle in the database that matches the keyword as your typing, which seems to save time.
With regard to reporting, we have segmented into 2 types. One being "My Reports" which is specific to your username. Detailed analytics based on your vehicle(s). One report in general that is very useful is the "Monthly Cost Breakdown" report that details total fillups, distance, average mpg, total cost and cost/mile for each month you have been tracking. Second being "Reports" which contain detailed analytics for any vehicle in the system. Regardless of the breakdown, I'm confident we are providing more detail than fuelly.
Development. With our staff and turnaround time you’re in control. If you have an idea for a report that would be useful well put it into production within 1-2 weeks and sometimes within days. We take pride in the fact that we are providing a quality product that is truly beneficial to the users using it. Meaning if you need a report to further analyze your MPG data let us know. After we work with you to spec it out, well build it and put it into production. If you have a cool idea or something that you would like to see in the application just shoot us an email.
I challenge you try our application, and let us know why you like ours over fuelly or vice versa. We are open to any feed back. Also if you can send us an excel import from any other site with your fillup data and your username in our site, we will import all of your data for free! Just send your data and username to
admin@fuelmileage.com and we will get it imported.