I have supported the company for over 4 years, and continue to advocate on their behalf, and for merino wool clothing more broadly, from sunny Brighton & Hove in England. I own about a dozen of their shirts, a mix of dress shirts, the discontinued twill utility shirts, and now some button-downs, in addition to the fantastic, market-leading boxers and socks.
I'm a subtly overweight, thin-framed man, and sized-up to a medium/regular (from previous small/regular purchases) so that the sleeves are the correct length even with a fully extended arm, and for a more forgiving casual fit over an optional base layer, at the expense of a slightly looser-than-needed collar (not so much an issue with button-downs worn open sans tie).
I have no complaints with regards to processing/delivery, customer service, product description etc., and the quality control has always been good, save for the occasional biteable runaway excess of button thread.
As a van-dwelling professional, I will never go back to cotton directly under my armpits, "downstairs", or around my toes (save for formal occasions which may prescribe it). However, we need to move beyond merino wool shirts PRETENDING to be cotton shirts in their colourway, namely using any off-white, simply in response to these being well established in the prevailing cotton shirt market. It's for good reason with cotton, and (with blues especially) for aesthetic congruence with many skin/hair/eye palettes; but wool is not cotton, and does not age in the same way.
Wool beiges/yellows over time due to exposure to sunlight, and as such in a variegated manner, depending on jacket/tie wearing, rolled up sleeves, under the placket and collar etc.. One can protect wool from moths, store/dry away from sunlight, protect from mould etc., but if the shirt is to be worn in daylight hours, then it will "turn" over time, and the affectation of it being a cotton shirt (with hidden benefits) is lost to it looking like a dirty shirt. This "turning" from off-white is inevitable, but can (and must) be factored in at the design stage.
Due to the "turning", I have hand-dyed a few of my older W&P dress shirts with dark brown dye to achieve a beige overdye effect with the retained blue checks/stripes, but due to the sun-inflicted variegation (pre-dying) these are no longer presentable beyond casual wear, even though the wool has plenty of life left in it (for example, abrasion-wise at the armpits). The synthetic white stitching remains, unfortunately and incongruently, even if one were to swap out the functional-but-meh white plastic buttons. Beige/grey/dark synthetic stitching (depending on the colourway) could help mitigate against this, and extend the unfurling life of the wool product (or linen/cotton thread, cost-dependent, but this would dye differently to the wool anyway).
The semi-spread collar is too stingy to work well with a suit/sports jacket and tie, at least for those with a discerning eye. Button-downs are less of a thing in England outside of casual-wear, and whilst one can appreciate the cost implications of additional material, if a shirt is to be "dress" (or in England, a normal shirt to be wearable with a tie and jacket), then "make it so" as Picard would say, or another company will step into the gap.
White cotton is practical (as cotton goes) because it can be bleach-washed, and sun-dried; merino wool of any colour cannot, for all it's other advantages. Beige-based, and/or darker colours more generally, are the way forward for a long-life product, both due to the "turning" factor, and to help mask the visually apparent build up of grime which the material can otherwise handle between (and after) infrequent hand-washing. It's notable for example that the founder's 100 day challenges have been with dark-brown (never available for retail) and darkish-red shirts, respectively.
Merino wool shirting has yet to come into its own from a functional aesthetic perspective. There is a space in-between Pendleton-esque hardcore overshirts/shackets, affectations of button-down cotton shirts (with benefits, but also under-recognised disadvantages/challenges), and perhaps Smedley-esque long-sleeved polo shirts. The advantage of a proper spread-collared shirt is that it can be worn with or without: a tie; additional knitwear (under or over); a tailored jacket/waistcoat; sleeves rolled up. The button up design is also more forgiving in terms of airflow/temperature regulation. A button-down design on a collar that is too stingy to ever flap about in the wind, and with nothing-to-shout-about plastic buttons permanently on display, is a suboptimal design, regardless of what Brooks Brothers would have Americans believe.
Wool & Prince is a wonderful, rightly respected brand, that has put in a lot of the ground-work for everyday merino clothing, but these blind spots may catch up with them as their following transition from being new customers to experienced return custom...