OrbitalDawn
Ulysses Everett McGill
Not sure what you mean by "basic" work. You need to have a outlook of the next 5-10 years.
Sure the 25% increase is great but will that sustain your job/skills growth over the next 5-10 years compared to where you are. Will you end up in a position where they can find a younger recruit to do the same and say cheers to you because you are now "expensive". What was the Old companies policy on increases? They may not offer you any over the next year cause you already came in at a higher rate. Clarify all these and make a chart of how things would look like over the next 5 years.
I would suggest you consider all these points and then take a decision. Good luck
Go to your current employer and show them the offer. Give them one opportunity to match it or even better it but if you are happy with something lower just getting close to the offer might do. Job satisfaction counts for a lot. A lot van also be said for honest upfront people and apart from the good job you did, you probably had a very good work relationship at the previous job. If that is anything to go by, I would guess you have just as good a relationship with your current employer. If this is true and I were you, I'd approach your current employer... they might even surprise you.
Both of these.
What are the chances of you being able to expand your role at your old company and perhaps incorporating what you've learnt at the new job?
Also, kudos on not burning your bridges. Right way to do it.