You must realize that I am only your average joe with no real knowledge of the industry but just interested in what is happening and how it will affect me in the future when I fly.
If you want the least hassle, book through an ATOL Travel Agent. Yes I have my own business - this morning I have rebooked customers flights where I'd booked an ATOL Flight Plus holiday at no extra cost to the customers. Couple of phone calls, job done. Package ATOL is a little different, if I booked one with Monarch Holidays, that will be a refund and rebook, if it was booked through another Tour Op as a package with Monarch flights, they will provide either alternative flights or a full refund. If you DIY book and don't get any ATOL protection, assuming you paid by Credit Card (which you must) then if you rebook flights with another carrier (potentially for more money), it's at your own cost as you have to claim your refund from the Credit Card provider. Dependent on how long that takes and your cashflow, some might not be able to rebook before their departure date and will miss their holiday if they can't afford to rebook. Under Flight Plus, if the flights were originally £500 and they are now £800, we pick up the extra £300 (well our Insurers do!) as long as the new flight cost isn't more than the total holiday price!