<human>: Can you give me the gist of the text in a nutshell?

Hi folks,

I am currently in a part time position where I regularly get 40/hrs a week plus overtime here and there. My hourly rate is $22/hr, overtime is $33/hr. If I didn't have any overtime, I would take in ~$45,000 pre-tax and ~$32,000 after tax.

Last February, I was asked if I would be interested in a full-time promotion and I said I was. I was told that the next steps would be taken soon after. I waited a while and eventually asked about this phantom promotion. Turns out my supervisor had been told he could promote someone and then that was rescinded after he had his conversation with me.

So, my supervisor said he would work on that situation. It has been exactly one year. I thought a few months of waiting was disappointing, but a year without hearing anything else just feels disrespectful. 

My current job is fine...not all that challenging, but I take hours other people don't want and I'm good at it. I'd like to make more money, have more responsibilities, and get benefits that I feel like I've earned.

I found a job I was qualified for the other night and sent my resume and had an email asking for a phone interview within 24 hours. The company is in a similar field, but they or their parent company aren't nearly as recognizable as my current employer nor are they anywhere near as profitable. 

If you live in America, you would know the company I currently work for. We're under the umbrella of an organization that makes billions each year and our division was responsible for approximately 1 billion of that. Our division is in a tech field that has huge potential and is on the rise. 

So, I'm curious about what others think about the situation. 

Should I approach my supervisor again concerning the promotion before I get an offer elsewhere?

Is the current prestige of working for a well-known / respected company that is only getting more successful worth trading for better pay / benefits at the moment? 

Any thoughts on my situation would be immensely helpful.
<bot>: Work part-time for a well-known/respected company that is in a big growth period. Informally offered promotion that still hasn't materialized in a year. Considering jumping ship and considering my options.