Can someone tell me the differences and what all goes about these processes

Hopefully, they're benched and tested to make sure they're in the same specs as a new amp, cleaned up cosmetically, and sent on their way.

There's very little "reconditioning" needed for an amp that's been in steady use, as long as it's not been abused or left to sit for a very long time...

So is it safe to say the internal workings of the amp are put back to specs or close to it and the cosmetics are the same as they were when it came in for repair?

yup. unless you have a bad repair guy

Everything should be back to factory specs if refurbished by the manufacture. But who knows if you buy it from a online reseller who had the "refurbished" by joe schmoe :-)

Right now I am running a kicker 700.5 I bought at ubid. It was refurbished by kicker, came in new box wrapped with all new sealed mounting/connectors/remote/etc a new one would and copy of manual/test results. It seems to work fine for almost a year now, I don't like it anymore, but it works like it should. It had a rub mark on the top, I polished 90% of it out so nothing is really noticeable. When I get a minute and it warms up around here, I'll be peeling it out and selling it. I want to setup so I can go active anyway and it would not work the way I want for that.

The amp should be repaired fully, tested fully to spec, burned in, outfitted with all accessories (though sometimes they don't), and warrantied by the place that did it. I only buy factory refurbs (done by the maker or their one anointed subcontractor), and I have no problem buying them providing I get a deal on them. You know the bugs were worked out, it is just a matter that it might have some wear on it cosmetically and most of the time I don't care long as its in very nice condition. I saw the same amp sell on ebay with a blown channel for the same price, maybe a fixed auction but others were close to that....not sure why. Also had a maxxsonics hifonics that was a refurb from them, I actually talked to a tech there about it and he told me they do it there. It was like new, even the letters on top were taped with foam inside the bag. He said they sometimes sell them in lots and places like ubid pick them up, sometimes those are ones missing accessories and so they get them cheap. So read the listing very carefully if you need everything like a remote or something....and make sure it is warrantied. Ubid only does 14 days or so, then the refurb place does what length they warranty (30-90 days?) so check the amp right away. Some refurb places will only fix or replace it, no returns. Just like anything, if you take the chance of it not being new then you should get a deal on it. If new is not much more I buy new. With amps I mostly buy used anyway, but that is just me.

I know a lot people that have bought refurb with nothing less but success.

I wouldn't scared of "Factory" refurb. Now that other stuff may scare me. Who knows tho.