No it wasn't to hard at all, getting the hang of using the flare, triple checking the proper length to bend and 2 broken rental flare tools were the hardest part. I bought a 25 dollar flare tool at autozone and the thing worked like a charm, made great flares and I ended up redoing all of the flares with it.
Oh also, remember to put the fittings on is very important before making the flare... ask me how I know... ooh and don't let the fittings fall down the line then add a bend to the line... thats a pain in the *** too. Overall it only took me maybe 2 days working about 2-3hrs a day...