ESX and VMs on the same datastore - pros and cons?

Hi all,

Planning to migrate from ESX 4.1.0 (348481) to ESXi 5.1. Currently the server (PE2950) is configured with 2 mirrored drives where ESX is, and RAID 10 as the second datastore.

I feel like we are wasting too much space for redundancy. I want to use all 6 drives in RAID 5 forming one datastore with ESX and VMs on it. What are the cons of this config?

Thanks a bundle!