If they're the same price buy one this month and the other next month. ELT is a little sweeter, richer, and Blanton's is dryer and a touch more refined. Both are good in their own way and you should have the chance to enjoy both. Which one first is the only real choice.
They will both be tried, in time. I can assure everyone of that! Price-wise, the ETL is $15-$20 cheaper per bottle - I've seen it everywhere from $26-$30 per bottle. Blanton's has been $45-$47.