Bundles Install vs 9.1 Upgrade

Our office is considering upgrading to 9.1 from 9.0. Currently we are 54 bundles behind and are trying to determine the best option:

1) Install the 54 bundles and hold off on upgrading to 9.1 for a few years

2) Install the 54 bundles and then upgrade immediately after

3) Upgrade immediately to 9.1 as the upgrade should fix all prexisting issues addressed by the bundles 

4) Upgrade to 9.1 and then install the 54 bundles

Additionally, if we do install the bundles, should we:

(a) Install the bundles in small batches and test between each session OR  

(b) Install all the bundles at once and do one big test

We are not necessarily adamant about the new features offered by the 9.1 upgrade and can afford to wait a few years. We are more concerned with fixing anything that is broken. Any comments would be greatly appreciated!