Never use Ifrit.
His attack seems to scale off of STR(or maybe the physical damage/auto attack on the book, rather than magical). It's 120 potency but hitting for ~120-130. Garudas 100 potency is hitting for ~180-190. Auto attacks don't make up the difference in pet alone, not even mentioning Contagion.
http://i.imgur.com/3XFBXwD.jpg
http://i.imgur.com/3XFBXwD.jpg
http://i.imgur.com/dfWmvnz.png
http://i.imgur.com/dfWmvnz.png
Reasoning on why I think Ifrit is lower: It's splitting the crits between a weaker and stronger attack, rather than just a single stronger attack. It's better to crit on a bigger hit than it is a small one, and if you have equal crit chance the bigger will win on the same timers.
Some longer parses(note the parser is 100% accurate for pets. Everything is logged, no DoTs):
http://i.imgur.com/pc1GaZs.jpg
http://i.imgur.com/pc1GaZs.jpg
http://i.imgur.com/7cQHHJu.jpg
http://i.imgur.com/7cQHHJu.jpg
tl;dr
Don't use Ifrit.
Ever.
