I can't wait to get my Nucleus together, tomorrow is the day.
Beside some light primer strikes that might just be bolts packed with grease or improper triggers, I have heard nothing bad so far about the Nucleus.
That reflects mostly short actions but I don't think long actions would be any different.
I'm not sure what features a TL3 might have over a Nucleus but I don't think the Nucleus is lacking too much, in a way I think it has more features than Mausingfield.