I am using airlift. I have installed 4 different of airlift setups for friends and haven't had any issues yet. If you get the heavy duty compressor it fits on the drivers side frame rail right below the firewall.
I have the firestone kit. Works great. I had hell wigs on my 450 and it was good also.
Its all preference.
I just like them where the stock bump stop goes, but that is preference also.