Both are Naim, from different ranges - the engineering approach is shared and the differences are mostly in power, connectivity and price.
| Area | Better | Why |
|---|
| Power | evenly matched | Effectively the same output - 70W against 60W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Room size | depends | We rate Naim Uniti Star Lite the better fit for a mid-size room, a large room and a very large room, and Naim Nait 5si for desk or near-field listening and a small room. Match the amplifier to the room you actually have, not the one you want. |
| Built-in DAC | A | Naim Uniti Star Lite has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | B | Naim Nait 5si takes more analogue sources - 4 against 2. |
| Use with a TV | depends | Only Naim Uniti Star Lite has HDMI ARC, so the television can drive it directly and one remote controls the volume. If the system is for music only, this changes nothing. |
A Naim Uniti Star Lite B Naim Nait 5si
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?
Neither runs away with it - they trade advantages. Let the "depends" rows and the speakers you already own settle it. If this sits under a television, Naim Uniti Star Lite is the one to buy - HDMI ARC means the TV remote controls the volume and there is no second box in the way. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Naim Nait 5si becomes the more rational buy.
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.