[mikestar13]

I wouldn't open this 1NT playing a system requiring 1NT on all 5-3-3-2's (which I do, most of the time), preferring to treat this excellent spade suit as a six cards. And if I won't open it 1NT, I sure won't overcall 1NT, where 1NT has more downside and less upside.

[the hog]

I would certainly open this hand 1NT. In this case I will overcall1S.

[Zelandakh]

In addition to the reasons already given I think a 1NT overcall on this kind of hand is a bad idea because the message sent is quite different from a 1NT opening. The overcall is generally less specific about shape and suggests to partner that there is a risk of a misfit. Both of these things make partner a little more conservative when competing, exactly on a hand type where we want to be quite bullish. I think the 1♠ overcall is clearly better here; as dealer the choice is a little more interesting and depends much more on system.

[gszes]

i am normally a firm believer in overcalling good 5 card suits when
reasonably able. This hand is a rare exception to me because p
does not need that much for us to make 3n and it will be easier to
get p to invite with nt than over a 1s overcall. This will be especially
true if p does not have spade support and an otherwise boring hand
with no dia stop (98xx).