I'm new here so if I'm not supposed to ask this stuff sorry, but I'm looking to buy kind of a knock around guitar (I guess you can call it that), but I can't decide between a js100 with a PAF Joe at the neck and a FRED at the bridge or a stock rg1570. I've played them both, but I haven't been able to play the js100 with the pickups I want. basically. would the modded JS be better than the RG stock?
I hope you mean a JS1000 or there's absolutely no contest.
R.I.P. My Signature. Lost to us in the great Signature Massacre of 2014.

Quote by Master Foo
“A man who mistakes secrets for knowledge is like a man who, seeking light, hugs a candle so closely that he smothers it and burns his hand.”

Rg1570 owns the JS100. the JS100 has an Edge III trem. go for the prestige 1570.
Ibanez RG321MH (Air Classic/Tone Zone)
Fernandes Telecaster (Twang King/stock bridge pickup)
Blackstar HT-20 (Scumback 55 speaker/ Tung Sol tubes)
TC Electronic Nova Repeater
Lava Cables Clear Connect, Soar and Mini ELC
Is the RG1570 used? Because I would find it really odd that you would be comparing two guitars of different price ranges.

Either way, go for the RG1570. No questions asked.
Heads will roll. Throats will be slit. Blood will flow like springs of water.