When you're comparing used rackmount options in the ups critical power category, the real decision is readiness versus headroom. The Libert Vertiv PSI5-1500RT120 and the APC SRT3000RMXLA are both used rackmount UPS units, but they sit at opposite ends of that trade-off.
Before you compare price tags, be honest about the load you need to protect. A modest network stack doesn't require a giant UPS, while a larger rack will demand more power. The right choice depends on whether you want a complete package or a platform you can build on.
Quick verdict
If you want a unit that can protect a modest load right away, the Libert Vertiv PSI5-1500RT120 is the cleaner pick. It pairs automatic voltage regulation with an LCD status display. If you need more room to grow and are comfortable with a project UPS, the APC SRT3000RMXLA is worth the extra setup. Both are used units, so some cosmetic wear is likely; the bigger differentiator is what you need to add after purchase.
At a glance
| Product | Listed Price | Capacity | Form Factor |
|---|---|---|---|
| Libert Vertiv PSI5-1500RT120 | USD 149.99 | 1500VA / 1350W | Rackmount/tower |
| APC SRT3000RMXLA | USD 203.62 | 3000VA / 2700W | Rackmount 2U |
Where each product wins
- The Libert Vertiv PSI5-1500RT120 wins on readiness. It was recently removed from a working environment and is closer to a plug-and-protect setup. The pure sine wave output and automatic voltage regulation are useful if you're powering sensitive electronics.
- The APC SRT3000RMXLA wins on scale. Its higher power ceiling gives it more headroom for heavier equipment. If you're consolidating several devices into one UPS, this is the unit that can handle the job.
Product notes
#### Libert Vertiv PSI5-1500RT120
The Libert Vertiv PSI5-1500RT120 is a rackmount/tower UPS with pure sine wave output and automatic voltage regulation, which makes it a sensible match for sensitive networking gear. The LCD status display keeps you informed at a glance, and the unit passed its built-in self-test with an "OK" result. The listed price is USD 149.99, the lower price in this comparison. The trade-off is headroom: it handles lighter loads well but isn't built for a full rack. It's also a used unit, so some wear is part of the deal. If your load is modest and you want complete protection, this is the more ready-to-run option.
#### APC SRT3000RMXLA
The APC SRT3000RMXLA is the higher-powered option in this pair, and it comes in a 2U rackmount format. That extra power is the main reason to choose it. The catch is in the details: it has no batteries included, so you'll need to add a battery pack before it can protect anything. The unit is also pre-owned and re-boxed, with damaged front bezel retaining clips and a defective rear USB port. The listed price is USD 203.62, which makes it the more expensive of the two. Buy it when you already have batteries on hand and need a bigger UPS foundation; skip it if you want a single-box solution.
Final choice by use case
Choose the Libert Vertiv PSI5-1500RT120 when you need a smaller, complete rackmount UPS and want the easier setup. Choose the APC SRT3000RMXLA when your load demands more power and you're prepared to handle the extra prep. If you want one unit that arrives ready to work, the Vertiv is the easier path. If you're building out a bigger critical-power setup, the APC gives you more to start with.
