Own the entire series.
First one is ok.Typical of a first entry of RPG series.
Second one starts to establish a personal Identity for the series. I thought the Dragon element was a step backwards but everything else was a good step forward. Sound was cool though very repetitive. Both BoF1-2 have terrible translations. Be warned.
BoF3 is the official establishment/Identity for the series. Does everything better than BoF1/2.
Breath of Fire 4 is my personal favorite. Step back in the Dragon/Map system but everything else was awesome. I do think Breath of Fire 3/4 were waaay to easy.
Breath of Fire 5 is like what happens when you combine an RPG with classic Resident Evil trappings. Breath of Fire 5 is also an example of game that was too radical of a change. I like it for what it is, but if need to settle my Breath of Fire itch I wouldn't choose this installment.