No single best amplifier here. What decides it is what you have to drive, what you need to plug in, and how much of the system you want in one box.
| Area | Better | Why |
|---|
| Power | B | Rotel RB-1582 MkII has more power - 200W against 160W into 8 ohms. That is about 1dB, which is a small step in loudness but real headroom on peaks. |
| Speaker load rating | A | Parasound Halo A23+ is rated down to 2 ohms against 4, so it is the safer partner for a low-impedance speaker. |
| Analogue inputs | evenly matched | The same number of line-level inputs (2). |
| Amplifier class | depends | Parasound Halo A23+ is Class A/AB and Rotel RB-1582 MkII is Class A/B. Class A/B runs warm and is the long-established mainstream choice. Modern examples of both measure well - judge by the rest of the page. |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | B | Rotel RB-1582 MkII is the cheaper watt - about $12 per watt against $16. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Parasound Halo A23+ B Rotel RB-1582 MkII
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both amplifiers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
Rotel RB-1582 MkII has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is.
What a spec sheet cannot show: how either sounds with your speakers, how the controls feel day to day, and what the app is like to live with - which is where most all-in-one amplifiers are actually won or lost. Power figures are the manufacturers' own and are not measured to a common standard, so treat small differences as noise. If you can hear both, that will tell you more than any row above.