Review Summary: Don't call it a comeback.
Let's go ahead and get one thing straight. This is not the same band you heard on Nocturne. This is certainly not the same band you heard on Midheaven. With Nathan gone, the band has not only undergone a huge vocal tone change, but also a musical style change. The same classical guitar interludes are still there, as well as blazingly fast sweeping guitar parts, but it is used more tastefully and as less of a gimmick.
So how does the new sound hold up compared to past attempts by this band" It does more than just hold up. It IS. Past attempts either went over very well, or failed terribly, yet still came off as rather cliche at times even it it was enjoyable. This time around, The Human Abstract actually make sense. Their music builds up to intense breakdowns, and then backs off to reflect on what just occurred. One could compare songs like "Complex Terms" and "Antebellum" to a classical symphony. They feature many strikingly different movements that all seem to fit together in a way that just flows fantastically. Even the bombastic breakdowns that in the past seemed ill-fitting just seem to add to the music here. The Human Abstract have sacrificed only the slightest bit of technicality to produce true musicality.
The new vocals are a huge improvement. Nathan had his good moments, but some things he did just came across as a toddler having a tantrum. The new vocals change styles depending on the song, but often feature heavily layered deep growls and occasionally a higher shriek. His clean vocals are incredibly smooth and controlled. Melodically he delves into some rich harmonies and interesting phrasings.
The point is, this is not the same band. Enjoy Nocturne if you'd like. Try to make it all the way through Midheaven if that's your cup of tea. Either way, you're not listening to the same band that produced Digital Veil. This band is far too polished, far too mature, and far too progressed to ever be compared to that band of the past.