Do you plan to wheel? The Toyota's IFS suspension is far superior to the Isuzu's. I know this because I looked into making ball joint spacers for them and by buddy has one. I spent quite a while under it and was amazed at the differences between the two suspensions. One (Toyota) was clearly made for off road use, the Isuzu just isn't. Also there are minimal aftermarket suspension upgrades for the Isuzu.

The over quality is not bad, the Toyota is better but the Isuzu is not bad.

The Isuzu's 3.2 dual overhead cam V6 is faster than a 3.0 4runner.

The Toyota will outlast it and hold it's value better as I'm sure you know.

Frank