Short term your schedule will get worse. Long term, catagoricaly you will see improvements in almost every area. Third year F.O. pay at Delta on the 737 you will be more than fifteen year 700/900 Captain pay at a regional on an hourly basis ($91/hr). Not to mention MUCH better work rules, including cost of living increases, double pay (thats $182/hr) for an inverse assignment should you choose to pursue that. The profit sharing program (5% this year) and automatic 11% retirement given to you by the company in dollar terms should put you above $100/hr by third year on the 737. More if you go to the 767 as many new hires are. Trip rigs, duty rigs, real crew meals on some flights. Eighteen year (top pay at most regionals) is around $99/hr and you are topped out, especially without cost of living increases. At Delta for example you get COLA but can also bid up to a larger aircraft for more pay or stay in the smaller MD or 737 for quality of life. You dont walk down stairs onto an icy ramp and try to pry open your RJ door on a cold aircraft....you walk into a jet way every time with conditioned air already on the airplane 99% of the time. Theres less paperwork at most Majors than at the regional level from my experience. At Delta you dont do a postflight inspection on last flight of the day at most airports....its a MX function.
You dont clean the plane or cross seatbelts on your break (unless you are with JB or similar LCC). You dont fly with 21 year old know it all kids that you have to flight instruct for the rest of your career (always worried about an altitude bust, etc and your ticket/job) while you know they are thinking they will be at a "real" airline in a year or two and dont mind talking about it all day. As mentioned ealier, a variety of flying, etc. In my experience, hotels on average are much nicer with a major. Hyatts and above are not uncommon. It keeps things interesting and fresh. A true long call reserve makes reserve duty much less painfull. Using really good reserve work rules at Delta where you can pick up a trip on a day off, credit above gaurantee and be comped another day off its possible to bank alot of hours with the same exact days off for the month. Works really well. Try that at a regional. Commuter policy and the ability to absolutely reserve the JS if you phone in first up to three days in advance reduces commuter stress alot. I dont know of any regionals that have this. Movies while you deadhead

Reserve transparency and the ability to see everybodies schedule....better for keeping the company honest, trip trading with friends and contacting people.
Bottom line, you will potentially be doing this for another 25 to 35 plus more years. Is it worth it to you to suck it up for a couple years to have 20 plus flying with better pay and a better overall job? Do you some day want to fly international with really nice layovers to take you familly along or fly a 787/ A350? If none of the above matters to you then stay at a regional and continue for the "quality of life" you gain the next 36 months.
PS- the next five years at the majors I expect to see some pay rate gains (not year 2000 numbers but decent gains ie 10 to 20%). With the lack of solidarity and all the newbies with SJS at the regionals dont expect much increase in pay or work rules. Lastly, the RJ market is mostly saturated now. Most of what will be happening now will be switching fifty seaters for 76 seaters. If/when Delta gets a hundred seater, some RJs will be parked.