Sorry Old chap had to bite.....
Its a no brainer. Go for the 737 and learn some airline disciplin.
Its easy to be disciplined in an airline as the mode of flying lends itself to repetition, at FR you will see the destinations that they fly to from your base and thats it. SOP's are much easier to apply in those cases as you know the routes and the likely curve balls that ATC will throw at you.
Now imagine jumping in your XL on a Monday and not knowing if the sector after next will take you N/S/E or west. CRM demands are greater as you will no doubt be spending extended periods with your other pilot including evenings out possibly and you must have that chameleon factor to be able to get along without friction.
In addition you will be encouraged/required to fly outside of CAS into smaller airfields, encouraged to join with other VFR traffic you will find yourself behind a PA28 downwind at 130 knots.
You will NEVER get that mix of flying at an airline, its why airline guys who to be honest in the main (sorry to generalise) stumble from one radar environment to another can take a long time to line train.
I know lots of Airline guys who cant file a flight plan. If you cant think on your feet join Ryanair.
Also regardless of weight and if requested you can see rates of climb and or huge rates of acceleration that you will never ever see in an airline environment. If you can handle that every day any boeing or bus TR will not be a problem going forward.