My experience with Tripp-Lite was terrible. We had two PDUMH20ATNET units at a colo facility and both suffered the same failure about six months apart. Basically a diode (D55) burned out in both cases. It turns out that this was a typical failure for that model.
Since that set of failures, we've used nothing but APC units for our critical data center installations. The only failure we've had was a stuck/broken start button. We've never seen an actual electrical failure.
That having been said, please consider this information anecdotal. Any electronic system recommendation is based on personal experience and rarely is statistically significant.
That having been said, Tripp-Lite failures cost our company significant downtime and added to my stress level. I won't trust them again as a result of that experience.
I have both tripp-lite and apc failures