I find Jazz to be noteworthy for the following:
- more likely to have an aircraft type without seatback TVs (may not apply to you) - if you're on an Embrarer you should still have TVs;
- more likely to have a younger crew;
- more likely service crew will be genuinely trying harder and enthusiastic but also less experienced (specific examples: a remember of the Jazz crew was genuinely interested in me explaining the differences between the wines they had onboard - on a different flight I was downgraded due to the negligence of the gate agents off a paid seat in J when a Y passenger without status was given my seat in J) --> I find this to generally be a positive as it means more passes through the cabin for service