Ryanair.
Despite my well documented hatred for the company, the money is good for a cadet and the training is world leading. I left some time ago, but everywhere I go in various sim centres around the world I, and any other ex Ryanair colleagues, always get a "oh you're ex-Ryanair? Great! You'll have no problems with this course. It's always a pleasure teaching ex-Ryanair pilots, you guys just get it".
It's set me up for my career, the training is so well recognised. It's even better than that at legacy carriers, but such carriers won't (and the pilots who have been at legacy airline for +30 years) won't like to admit it. Some airlines won't sim check Ryanair pilots during assessments, but they will everyone else.
The 737 is a handful to fly, but if you fly that well and get a good grounding (ie at Ryanair), then you will find that any other modern jet is an absolute piece of cake.