I think that's a personal decision. It all depends on what's most important for you and your business.
What I did:
I saved up my MRP to purchase the Lifetime Custom Prestige Domain For SFI Affiliates: http://www.tripleclicks.com/detail.php?item=182069
After that I use them to purchase 1 TCredit to gain VP since one TCredit is 102VP.
For my business the most important parts are:
1) do my to do list daily
2) earn as much VP as possible
3) advertise daily