If you feel the need do it, then in about a years time you might be back
If you are not feeling 'one' with the latest zed then it's no real loss if you change. You can always come back later and pick up a good one. At times I have felt like a change but there is little out there in the budget to do a deal so i'll stick with the devil you know, besides I would regret selling mine when push came to shove.
No harm in test drives and getting a feel, crunchtime is when you start talking numbers and the trader starts running the rule over yours (if p/exing)