seems to me that the new replacement 72 pin connectors available today lack the quality that the original connectors have. ive used a few of the new connectors that just never worked properly. i had 1 new connector with the plastic housing warped a little. when i take an old connector, properly reposition and thoroughly clean all the pins, each one ive fixed this way has worked flawlessly. what do you guy think?

Yep, I completely agree.

I still have the original connector from the NES I "repaired" with a new connector... After using it for a month or so now, I'm starting to think about cleaning up the old connector and swapping it back in.

I have a connector I pulled from an fc twin. You can hardwire it to the nes board and mount it to the loading tray. Holds the games well and will work 99% of the time. $10 and it's yours.

Yep, unfortunately the replacement 72 pin NES cart connectors are poor quality. They're often advertised as being gold plated, but I doubt any of them contain any gold, just "gold coloring." The replacement connector I purchased was too tight and I had to force the cartridge in. Even then it didn't really seem to work better. Nintendo's original design for the front loader's "zero insertion force" cart connection is terrible, which is why they released cleaning kits and later a conventional top loader NES.
I have had good luck using the Digi Key connector, part #A31721-ND although it requires some time consuming rewiring to install. It does have real gold plating. Even if it isn't the exact pitch as the original, I've found its close enough to work great.