Do you think the n'lock is strong enough to carry a loaded handlebar bag without any issues?
Mine permanently carries a loaded handlebar bag with heavy stuff in it (paintbox, sketchbooks, camera, backup battery for my iPhone, metal wallet, seat cover, etc). The handlebars themselves are loaded up with heavy Brooks leather-ring grips with cast ali ends, and considerable gear and controls. More, though I have Big Apples, which are excellent suspension front and back, and run them at very low pressure (under 2 bar for an all-up weight north of a quarter-ton), I use them to ride at speed right through obstructions that would break a lesser bike, so that the stem takes a huge amount of stress as the bike requires to be steadied. The n'lock seems to be immensely strong; it shrugs off this kind of hard use with disdain. Swiss engineering may not be boutique-elegant, but it slugs right back with the best of German engineering...
Also, is it the adjustable model you have?
No, I have the fixed model. I ordered the adjustable model, because my bikes always have adjustable stems, but they didn't have it in stock in the right color (black), so I took what I could get. It was a mistake: the adjustable model is much more convenient.
If so, does it suffer from the incessant creaking noise that all adjustable stems seem to suffer from.
I doubt very much that the adjustable n'lock will creak, but I think there is at least one adjustable n'lock owner here who can give you an answer from experience.
...the incessant creaking noise that all adjustable stems seem to suffer from. I have bought two adjustable stems in the past, and although I loved them, had to replace them with fixed stems because the creaking drove me crazy.
Sounds like you either cheaped out or were immensely unlucky. I have adjustable stems on all my bikes, and have had since forever, immediately fitting one if the bike comes without because I sit very upright and like using the adjustable stem to gain handlebar height. None have ever creaked. But I'm not a weight weenie, and I have only stadsportief (fast but hefty commuters) and touring bikes, so I tend to buy quality engineering that lasts forever before I worry about price, and I don't even ask how much it weighs.
On my Gazelle I have their outstandingly convenient but unfortunately proprietary Switch stem, which is toollessly adjustable, and absolutely wonderful; unfortunately, the last time I looked it was only available for 1" threaded steerers...
On all my other bikes, except the Utopia Kranich, I fitted the bomb-proof Humpert Ahead Stem Swell Eco, whatever all that means... You need tools to adjust it but once adjusted it is rock solid. It is lighter than it appears:
On my everyday utility/recreation/exercise bike, a Utopia Kranich, I have the n'lock, not adjustable.
None of these stems make the slightest sound. On smooth tarmac, on the white line, in the middle of the night without cars in my quiet country village, my bike proceeds like a ghost, just the sigh of wind against spokes. (I'd like to conduct this test in front of the graveyard, but the blacktop there is rough...) I'd hear a creak in the stem, for sure, and it would drive me bonkers until I fixed it.
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I were you, rather than worry about noise from the n'lock, if your bike will be exposed to a lot of driving rain, I'd make sure I was prepared to service the n'lock every few years according to Julian's instructions in this thread. It's no great concern to me even on my near-zero maintenance Kranich, which like all my bikes lives inside in heated space and is rarely wet (I'm old and not in a condition for extensive tours), but presumably your bike is more actively exposed to the elements, so a fiddly (springs!) service may be a small consideration.
Good luck. Fitting and usage reports are always welcome, even if we already have some.