I use a Tekonsha Primus IQ with the vehicle specific wiring harness on a Frontier. Took me 5 minutes to install and two weeks to find the best location for it (under the dash above the center console). It is a proportional braking system, which was the feature I most desired. The Tekonsha Primus IQ may not be "the best", but it meets my requirements.
Here is a comparison of the major differences between a P2 and IQ to see if you need to pay up for "the best" or whether you can save some money with an IQ.
1) The displays are different. The IQ tells me its connected, the boost level, and the braking level in a bright red color. I'm satisfied with the IQ display.
2) P2 features a rotary lever for the manual braking feature, while the IQ uses an older style slide lever. Call me old fashioned, but I've always used slide levers.
3) The P2 has a 360 degree mounting range the IQ can only be mounted in a range 70 degrees up from level. I mounted my IQ nearly level, so 70 degrees was more than adequate. If you need to go past 70 degrees, then you will need to pay up for the best.
4) P2 brake controllers can be used with electric over hydraulic trailer brake systems, but a IQ cannot. I've never needed to use electric over hydraulic and my Casita
definitely does not require this feature. If you need this feature, you must pay more for a P2.
5) The P2 also features a more advanced self-diagnosing system than the IQ that checks continuously for problems. Here again, the only interaction I have with the unit is the display, which tells me its connected and functioning.
7) A P2 controller will work with trailers that have brakes
on 1 to 4 axles, but an IQ will only work with brakes on 1 to 3 axles. My Casita has only 1 axle
. If you need four axles, you must pay more for a P2.
So if you need to mount the controller past a 70 degree angle, need electric over hydraulic brakes or need four axle
braking, you must pay the additional cost for "the best" over an IQ. The IQ is more than adequate for my needs, is plug and play, and uses the same proportional braking system as the others. So I saved a few bucks and bought an IQ which works perfectly with my Casita.