Lots of 91/135 guys get hired just as well. Look at the hiring requirements at legacies...TPIC, 4-year degree, no requirement for 121 time that I can recall. I personally would value the TPIC you have an opportunity to acquire right now over the chance of getting on with a regional and stagnating in an FO slot with reserve, commuting, and the like. Get your PIC, ...then... consider jumping over for 121.