Well there are only 1,000 NNN.ca, and 17,576 LLL.ca, so NNN is more 'rare'.
I haven't seen many NNN sales, but if it starts with a '0' it is probably less valuable than one that doesn't.
I would say a good LLL is better than an average NNN, for example I'd rather have nse.ca than 835.ca.
But I'd also rather have a good NNN than most LLL (that aren't words), like 514, 416, 247, 360 would be great NNN to have. Great thing about numbers is they are fairly universal and understandable to everyone. Some NNN can also represent birthdays, like 324 would be March 24.