I used the Templar follower for leveling and I agree it's the best follower before inferno, because he was effective at healing you.
In Inferno, all he does is wasting his heal to heal himself, die, or just can't heal you because you got ont shotted.
p.s. My Templar has 70k hp
I started to use the Scoundrel as my follower from Act 2 to Act 4 (currently on Inferno Diablo so no more follower but anyway) and I love him.
My Scoundrel has 70k HP and 2k DPS, while it might be a low dps increase (I do 90k with sharpshooter), his spells are really useful (slow mobs, vanish so he doesn't die, increase my dps by 10% for 3 sec each 6 second I crit (I always crit), and has a very cool arrow with a stun.
Best follower for leveling: Templar
Best follower for inferno: Scoundrel
p.s. I use the enchantress on my inferno barbarian, never tried seriously with my Demon Hunter but I think the scoundrel does more for the DH
The Templar is good for initial stun, passive even when dead, and the MF/GF bonus. Give him a MF Weapon, Shield, Neck, and two rings and that's a bit of MF for you. I don't expect much of Companions to be honest.
Lower your expectations and you'll find them useful.
P.S. You're using P.S. wrong. You can't just P.S. in the middle of a text. P.S. is POST script.
P.P.S. Just like how you used passed instead of past.
P.P.P.S. There's nothing after inferno.