If you choose to buy a warranty make sure you read and understand the fine print. As with any insurance policy the devil is in the details. I worked as a mechanic and shop foreman in a new car dealership for years and part of my job was calling in customer claims for repair.
I am not familiar with Fidelity. The best ones that I dealt with were from the manufacturers. The one thing that I would suggest is to keep all of your receipts for any service and especially maintenance work like oil changes, coolant flush, Trans service, brake fluid flush,timing belt and tensioner service. etc....
I ran into several cases where customers claims were denied because they failed to prove they had maintained their vehicles according to the manufacturers service recommendations.
The other thing to watch for is to make sure subsequent damage is covered. For example, if the timing belt breaks and the valves crash into the pistons, will they cover the removal and repair of the cylinder head? Water pump fails and the engine overheats causing internal damage, is the engine damage covered?
Last but not least, find out what the maximum hourly labor reimbursement rate is. Some companies would not pay our dealership labor rate leaving the customer stuck with the difference. Like I said, the devil is in the details.
http://www.consumeraffairs.com/auto_warranty/fidelity.html
Interesting read.