I did LAX-LGW a couple of weeks ago in Premium Light. Super nice crew and the food was actually better than my last United Polaris flight - which is more a United problem! Full open bar on board. No wifi on Norse, even though the planes have it installed.
The checkin at LAX a bit odd as it at T1 next to Southwest but avoids the mess at TBIT security as there were no lines early afternoon and the bus takes you to the far TBIT island. Norse do not to Pre so this was actually a plus.
One person in front of me in line at checkin. They absolutely were enforcing the 10Kg limit on the carry on, even for small excursions. The personal item was not weighed. Pushed off the gate right on time.
They have been cutting flights very significantly to LAX and abandoned SFO. My flight was full in Premium but very light in the back so probably a smart move to survive, which I hope they do! LGW is a much quicker airport than LHR.
Like TomCayman, I do one ways and Norse were a bit greedy on the way back so did a last minute pretty cheap miles ticket on United in premium plus. That flight on an ancient 777 was empty in the back and full in Polaris and Premium, so winter on the Atlantic has started.
Would strongly recommend them in Premium with the caveat that they may not survive (again) long term.