Welcome to the forum. I'm also a Sr Sales Engineer. You will find that the Sp3 is a great tool for any SE. The pen will make your WebEx's come alive. Rather than doing a PPT, you can open OneNote and start drawing your customer's environment. This interaction turns a boring WebEx into a productive meeting where the customer is actively engaged.
I'm a senior consultant for NetApp and that's exactly what I do!!! It's amazing to hear the feedback as you run a WebEx and actively markup drawings and schematics in front of customers as they watch. Just demoing that one function has at least 3 to 4 guys I work with actively wanting one now.
I will tell you though that I hope the very recent throttling adjustment gives me a bit of a boost on my i5 256GB model, as I've been able on many occasions to bring this thing just about to its knees with some of my Visio drawings :-D