Hi,
Firstly, I should thank you coz I look forward to your SC explanations. Honestly, 680 isn't a bad score. But as you said, 2 yrs exp. might be a problem. I'm sure there are other ways to make ones profile look stronger - namely community services. Bschools are big on that.
But if you feel that you can pull out a 750 or so, then go for it. Perhaps, you can apply to a few for R1 with this score and give the next one around November, before R2. Just give it a try.
How was your experience on the D-Day? The quant and verbal sections, were they reflective? Even, I'm not very strong at quant or verbal. I have to work on all aspects of GMAT. What is your take on quant? Can you elaborate? Since you are very good at SC, I'm sure it might not have been a problem, but for me it is. Could you please throw some light as to the most reflective materials? Thanks and good luck.