I have the same hosts as you and had a similar dilemma. Only difference is I've loaded it with 12x 600GB 15000 rpm SAS LFF drives
Here is a test that HP published with the performance of the P2000 G3 SAS in various RAID modes:
http://h18004.www1.hp.com/products/quickspecs/13551_div/13551_div.HTML
RAID Type RAID10 RAID5 RAID6
Sequential Reads MB/s 1,650 1,650 1,650
Sequential Writes MB/s 850 1,350 1,100
Random Mix IOPs 60/40 Read/Write 23,500 16,000 9,800
Usable Capacity in my case 3,6TB 6,6TB 6TB
So 30% less performance average between RAID10 and RAID5, but 45% more usable space. Hmmm. I think I will go with a mix of RAID5 and RAID10. Of course the test was setup with 12 vdisks with 12 disks each (raw i/o), but still it's an indication.
I also heard it's best to create a big vDisk and then just split this vdisk in 500GB LUNs instead of provisioning several vdisks.
Do you have the dual controller version or single controller? Another consideration is that if you only have one vdisk the second controller won't be doing anything.
My intended use for the P2000 is for a vCloud integration manager proof of concept (1x management cluster with 17 VM's and 1x compute resources cluster with 30-35 VM's) So after considering these points in my case I think I will go with:
Vdisk1
4 drives in raid10, raw capacity 2400GB, usable 1200GB, presented to my management cluster as 2x 600GB LUNs (direct connected to server via sas 6gb). I have to run around 9 VM's out of each LUN.
Vdisk2
8 drives in raid5, for usable capacity around 4,2TB to be presented to the my compute cluster as 8x 600GB LUN's via sas direct-connect. I think I should be able to run 5 VM's off of each LUN.
PS. don't forget to install the ESXi plug-in for VAAI integration!
PPS. for VDI performance check attached whitepaper