I was not a big fan of Gripshift back in the day - preferred Shimano RF shifters - but recently began to appreciate Gripshift shifters because they are reliable and can be found cheap.
I'm in the same camp. I've replaced every SRT Gripshift set of shifters that I'd come across on my own bikes with other options...but recently bought a '97 GT Vantara and it has SRT400 Gripshifters and...I've left them on. It has an Acera X 3x7 drivetrain (crankset not recalled) and the thing just shifts perfectly in every reasonable combination. In the middle ring, I can traverse the entire cassette with no cage rub...and then up- or down-shift on the front for the additional range when needed. Small-small will drag a little bit, but I don't use that combo. Large-large is also not optimal...but I don't use that either. Middle-all works great. I have a lot of experience re-cabling bikes and adjusting drivetrains, but I just swapped the handlebar to a wider bar and just carried the original Gripshifters with cables over to the new bar. It just works too well for me to want to mess with it!