I have been thinking of making the same move myself, recently.... Tired of the regional kool-aid and shenanigans; used to fly part 135 charter and it was much more fun. I would do it if it makes you happy. The 135 time will make you competitive in my opinion due to the customer service experience. Southwest and JetBlue take great interest in part 135 corporate, and I think both Delta and United have been known to hire corporate/charter pilots. You have part 121 time, so no worries there. There is a reason why the app asks whether you have part 121 and part 135 time. It looks better--but it most likely isn't the magic element for being hired if the candidate has black marks in other fields.