Vintage Longines from say the 1920s through to the 1970s are often exquisite. In those days they were at the top of their game, and the industry in general. Really high quality, beautiful watches with a long-standing top tier reputation. Love to wear some of those golden oldies.
In recent years they have repositioned themselves, more modestly yet at that quite admirably: some (not all!) great looking, very well finished watches with adequate - sometimes COSC level - movements (derived from proven ETA’s typically), at reasonable price points somewhere between $1,500 and $3,500 mostly. Again, a proper choice to consider in quite a few categories.
In comparison to most other offering in that segment, I think Longines are punching way above their weight. I find that refreshing and very good for both consumer and industry: Longines definitely help keep the game in the mid-market lively!
None, really.
Got some inherited and/or very carefully chosen vintage watches (1920s through 1970s) which I absolutely adore, each and everyone of them. Had one sort of miss-buy over the years, which turned out to be rather fragile mechanically, so ultimately traded that back (proper dealer). One or two still on wishlist, searching for a solid example, which takes time (no hurry there at all).
Also own a few new, relatively (but not overly) expensive watches, which I only bought after serious consideration and comparison to all manner of alternatives. Like those a lot, wear them when appropriate, no regrets. There are a few still on my ‘wishlist’ that may survive the ongoing pruning I do of that list, so which I may end up buying down the line.
And I own a good handful of micro-brand watches. These are predominantly for fun and novelty, and frankly cost so little that they do not interfere with anything else. I am slightly faster and looser purchasing those, but still only buy only 10-20% of what I come across and (fleetingly) like. So perhaps not that surprisingly, none of those have really disappointed: I know what I got them for and why, and that is exactly what they bring.
My only overall hesitance is the simple fact that in the end, the more watches I buy, however carefully elected, the less I get to wear each of them on average. First world problem.