Oberon has been in Warframe for years, many years. So much so that he felt like the most outdated, but still fun and nostalgic, frames to use. But as certain other frames like Hydroid got buffed, and certain pieces of artwork were made, it was high time for Oberon to get the rework touch. Included with The Vallis Undermind were many things. Whether that was Nokko, Arbucep, or the Thornbak. But the most important addition of all was his newfound power to get his wife back. But before we talk about how good the rework is, here is our recommended build for him!
Oberon Post Rework Build
Below will be our build for his prime variant (that you can use the same for his normal variant) that you will need no forma for:

For starters, going for a well-rounded build is important. It ensures that he does not lack in any area. Using Archon Intensify is important as he offers passive heals. Combining both Smite Infusion for team damage buffs and Hallowed Eruption for more duration of his third ability is a major boon. Arcane Reaper is a must to ensure he has even more armor and health regen, alongside Molt Augmented, offering more power strength over time in missions. Rage will help keep his energy full for as long as you need it to.
Below will be the Archon Shard placement for the build:

Obviously, you can change these out for what you prefer. But having just a little more armor and health and power strength, and duration is a boon for him.
Oberon Post Rework Review in Warframe
Now for the important part, the review of his rework. Smite is incredibly strong, and I love using it to instantly kill eximus units and the enemies around them. Hallowed Ground and Renewal pretty much work the same, but have increased buffs and functionality across the board. Reckoning still works the same, but strips armor, which is cool to use on heavily armored enemies. His new passive functions like mesmer armor, but is more restrictive to a degree. However, it is still a much better passive than before. Oberon clears and tanks in Steel Path content, and can finally be a go-to frame beyond nostalgia.