Which company has done ARM development right?

I agree with corestar.

In my minor brush with using Altera SOC any support was farmed out to rocketboards.org

Little support from Altera, and as a beginner in things SOC it wasnt much fun.

They are the only tools Ive tried

I think the problem stems from the fact that Altera were late to market for the Arm SOC parts, so everyone took Xilinx parts (Zynq). Then they basically gave up on the market as they'd lost to Xilinx and focussed on the 10 series. Then Intel bought them and they're moving away from embedded and becoming CPU accelerators, with a big push with OpenCL.

If you check the posts on this forum, a lot of them relate to Open CL.