Having been to both stadiums, I personally thought it was hands down GESA.

Ballpark Digest, a nationwide publication and website, tracks all things baseball, especially minor league teams.

They recently held a contest, to see which Single A 'short season' (there's long A and short-season A in MLB affiliated baseball) park is the best in America. The contest was among short season A teams who have major league affiliation. The Dust Devils are the Class A farm club for San Diego.

Out of several dozen, the finals came down to between GESA Stadium, and Spokane's Avista Stadium, and GESA won!  There's no better place to watch a game on a summer's night than out in West Pasco.

Congrats Dust Devils!   You can see more of the contest, and Ballpark Digest, by clicking here.