Mart,
Congrats on your purchase! You're goin to love it.
I prefer the Prvi 286 grain RNSP over the 270 Speer because the Prvi expands properly, holds together well and penetrates deep. I have found the Speer 270's to be much softer. They over expand, break up and don't penetrate nearly as well.
I'm sure Daryl and Rod will chime in on this as they have a lot of experence with them.
Looking forward to seeing photos.