Hifonics really isnt a bad brand. I probably wouldn't mess with their subs, but their amps are reliable enough to justify the price.
I have a 1206bx, idk if its the bxi or not right now, but its running solid two ohms pounding a 15 to death in my trunk.
As with any amp, if you treat it correctly, its not going to die on you. Generally amps are only as good as the owner running them. Dont crank your gain to distortion and clipping and your home free. Also keep ur voltage high enough to run it.
The PDX's are great looking amps, but they seem too expensive to me. near 500 for 1000watts just really isnt that solid of a deal. The small footprint is nice, but if ur looking to save some cash u can get alot more power from a hifonics amp.
So thats my 2 cents. that i have a refurbed hifonics amp an it works fine.