NAD M33 or NAIM UNITI NOVA?

I have never heard that Hegel.  Can’t say how it would compare. 

I had Naim Uniti Nova and can vouch for it. They are amazing for the price and they sound very musical. Don't go by their wattage, as they are very conservatively rated. They can drive most speakers with ease. They look and feel luxurious too. You might get for good discount now as they have been there for a while. 

That’s what I said. Don’t go by low wattage of Naim nova. They rate it very conservatively. I used them with my aerial acoustics 7t, which is 89 db, with ease (never crossed 50% on volume level: for loud music, max 55%). It is the quality of the watts and current delivered. Even their Uber expensive amps are rated conservatively on low side, but people who know the brand, understand that they deliver much higher in both quantity and quality. There is something very musically addictive quality in the nova (and Naim in general) that makes it very special. I wish I had not sold it and just kept in secondary system. I still have Naim uniti atom in other system and am never going to sell it. Just my 2 cents. But, of course, if you can listen to both and let your ears decide for you, that will be ideal. Good luck. 

I’ve heard the Naim at a local dealership, and I enjoyed it very much. I have not heard the M33, but I’ve listened carefully to another amp using the PuriFi modules, with a very positive reaction.

So, it seems to me you may have two good choices. Of course, the M33 has Dirac, if you have any interest in digital room correction, and I believe it also will manage one or two subs. It has more power, which could make a difference. Those all are nice features.

My suggestion at this point is, if you are thinking of buying new, try each one in your home and see what you think. How they work with your room and speakers (and ears) is probably going to be the key issue.