Yes it really is a lovely tune – I have been playing it for several years now. It is also known as Madame Judge and is one of O’Carolan’s more classically styled compositions for a patron – especially with the jig ending.
I recommend playing the piece in the following way (though this is just personal choice – but has served well at harp competitions/music festivals etc): Play 1st part & repeat, play 2nd part & repeat, play 1st and 2nd parts again in same style. Then move to the jig to end the piece. The jig however can/should (you decide)
My suggestion is to go for the latest edition of Donal O’Sullivan’s biography, in one volume (black cover, second title down). It contains every word of the original two volumes, plus an appendix I wrote concerning some newly-discovered material from a manuscript in Scotland, and some other updates. (The first edition is about 60-odd years old.)