I towed with an Activator for years until about 1999. Worked fine as long as you understood what it does and its limitations. When I moved up to a bigger 5er and a diesel tow vehicle, I upgraded to an Activator II. I towed that 5er for over 11 years and 100,000 miles with that Activator II. Same comment - it works fine if you understand its limitations. Then I sold the 5er and the diesel and downsized to an F-150 and a small TT. By then the integrated trailer brake controller (ITBC) was a factory option, so I ordered one on my F-150.
The ITBC is much better than the time-delay Activator or Activator II. If your truck is new enough that an ITBC was a factory option, then your best bet is to install the OEM ITBC. It will cost more than a Tekonsha Voyager, but I'm glad I have the ITBC on my F-150 and would not want to go back to my Activator II.
I don't have any experience with the proportional controllers. Most owners seem to like them.
Grumpy ole man with over 50 years towing experience. Now my heaviest trailer is a 7,000-pound enclosed cargo trailer, RV is a 5,600 pound Skyline Nomad Joey 196S, and my tow vehicle is a 2012 F-150 EcoBoost SuperCrew.