Not particularly, if those are my two options I'm picking Pomeranz for Espinoza all day every day. People are acting like Pomeranz is some chopped liver, but he's pitched extremely well this season, and added a very effective cutter mid season that has made him a much more complete pitcher. He's also pitched better away from Petco than at home. There are questions about his ability to handle the workload a bit since he's never pitched a ton of innings, but outside of having slightly less innings pitched this year Pomeranz has outpitched Julio. Julio definitely is more safe in that he's likely to pitch well throughout his contract, but Pomeranz arguably has more upside given the numbers he's put up this year.
Not to mention Julio's HR tendencies make him a really bad fit for Fenway. Which is another reason the Rangers probably aren't big on him, he'd be a horrible fit because of that in their home stadium.