My input may not be of much value to you because I'm not doing the installation but I went with PTB because their reputation seems to be very good. I didn't check the other place you mentioned as I actually had not heard of it. The installer is coming to my house on 2/3 so I will know more then. I didn't price anywhere else because I really wouldn't know what parts or tools I would need. It will cost more but some things in my world are better left to the professionals. Another reason is they are headquartered in Oklahoma and so am I.
If the parts are the same I would go with the least expensive.
2020 F350 Platinum, srw, lbcc, 4X4, 6.7 diesel, 12,400 GVWR
2020 Pinnacle 32RLTS