for me it would depend on what your rights would be in the event of layoffs.
the governement agency i worked for had a system where your seniority operated on several factors-
there was your actual employment time, then the time within your current classification, so if layoffs within your classification occured and you were the lowest on the totem pole (so you could'nt take seniority over another person), they looked to weather you had seniority over someone in the last classification you held. if you could you could demote (vs being layed off) into that classification, if not-they kept looking to every classifiction you ever held before you were layed off.
NOW-if you had moved to a different department with the same government entity it got trickier. some had policies where in the event a person who had worked for us previously could, in the event of layoff-take "bumping" rights back into our department, some other departments did not (and it was all written up in the union contracts that individual departments could do this).
for some people this works out fine, for others depending on the situation and where they enter into a promotional ladder, it can be the pits. i had one co-worker who managed to qualify for and effectivly jump over 2 positions that people usualy held prior to the one she accepted. she loved it for a long time-until massive layoffs occured. since she was on the lower end of the totem pole seniority wise, when layoffs hit while all of her impacted co-workers who had gone the traditional route of promotion only demoted down one classification (returned to their old rate of pay), she could only demote down to what she had held, BUT the m.q.'s for that had changed and she no longer met the qulifications so she had to bump down to the next lower which was a 30 or 40% cut in pay
i'de also look to what the new job responsibilities are-$3000 a year works out to $250 a month which is less than $1.50 an hour in salary increase. are all the new responsibilities only worth another $1.50 in pay to you (and will it bump you into a new tax rate, or cost you more to be working those weekends-esp. if childcare is a consideration)?
if the job is in any way, shape or form going to change you from a non supervisory or non lead employee to one who is-i speak from personal experience and say it is in no way compensating you for this (anything involving supervision or being a lead where you still have to do some supervisory tasks within a government agency is worth WAY MORE than less than $1.50 per hour more than whatever you are being paid now).