Based on silicon and mfg or based on support and software support?
And at what quantities?
Yeah, last year Qualcomm was all the shiz. But can you move 100K+ parts/month? No? Then it's off the table.
Broadcom, Nvidia, even TI (worse parts and massively worse support, IMO) same, same same.
Bottom line? I'd recommend Freescale 9 times out of 10 for any of the medium to small players if I was looking for a high end ARM SOC.
For the smallish player Freescale is you best supported higher end ARM SOC. The fact that they have almost (or none?) of their own custom IP works in your favor.
Need a tweak to the VPU or GPU interface [kernel change] on TI, NVidia, Boradcom, Qualcomm ? Answer -- not possible as they licensed the IP or giving out any programming information about the IP (NVidia .. looking at you) is a non-starter, even under NDA, assuming the above 100K (or 1M?) / month is not already pre-purchased.
If you are looking to build 10M phones your damn right to go to Qualcomm .. the LTE alone makes it the cheapest option. Of course you just have to do 'whatever Samsung is doing' because the support for customer #2 is pathetic -- but far from non-existent.
Perhaps your IoT project has no business using a higher end ARM SOC and you *should* be using a low end ARM Cortex M0, M3. or. M4. My preference in this space is an M3 -- STM32L, likely because I have used it successfully. However there are many options in the low power ARM space, lots of which are better targeted for IoT (or pretty much anything else with a dedicated purpose). A high end arm SOC is a 5 year old PC on single chip. HowTF is that a 'thing' for the Io 'things' ?
Kids today .. git off my lawn.