I use the Rockler controller. It looks a lot like an HT unit. But it seems to work better. My HT one died after about 10 hours of use.
I must be honest. The first Rockler one didn't work right out of the box. One e-mail to Rockler and I had a new one in a week. Didn't have to send the old one in nor take it to one of their stores. Great customer service. But beware none of these less expensive ones will work with Soft Start tools.