In 1999, the first cable change on my SRT-600 gripshifts took me 3 hours. Now I can do that style (with the internal cable stop) in ten minutes per side max. MRX under-the-rubber cable stop style takes me 5 minutes per side. The side entry ones are almost as easy as MRX but the cable end tends to get wedged in so add two minutes to grab a scratch awl and dig that cable end out - 7 minutes per side max.

This is how easy an MRX change can go, sometimes the cable doesn't feed 'round the bend but it only takes an extra minute to pop the hatch off, feed cable, then pop the hatch back on.