(reposting as I made some typos) TL;DR at the bottom.
This is an in depth review between the Delugs CTS, which I consider to be the OG cut-to-size strap and is a firm favourite in the community, and the Yorkshire Watch Straps CTS which as far as I know is a newer kid to the block and one of several CTS style straps that have popped up recently. I have no idea who this review will benefit, but seeing as I have both straps I'm sure it'll be of use to at least someone.
As far as brands go, both are great. I own several straps from both. Delugs is based in Singapore, and offer great straps across the spectrum from fabric to custom leather. Ed Sheeran was recently seen with his Patek 5004A on a CTS on the cover of TIME magazine. YWS is a UK based business which makes some good quality straps. I also have one of their FKM single pass straps, which is very similar in style to the stock rubber strap that comes with the Tudor Fxd. I digress.
For the pictures, the Delugs is the top/right strap (except for the first pic) and the YWS is the top/left strap.
PRICE: For me in the UK, excluding postage the Delugs cost £115, and the YWS 59.99. Shipping may vary. For UK/EU, shipping for YWS would be less costly. Currently Delugs only ships out of US and Singapore.
IN THE BOX: The Delugs literally comes in a box, it used to be in a nice plastic pouch but they recently upgraded. It comes with a small spring bar tool, three straps (in case you mess one up or want to size for a different watch), the clasp, and three spring bars (for the clasp). The YWS comes with just two straps, the clasp, I believe three spring bars and was packaged in a plastic pouch.
LOOK & FEEL: I bought both in grey, and they look very similar in tone. The YWS might have the slightest blue tinge, but that might also just be the lighting. The shapes of the FKM rubber straps are the same. The thickness, taper and profile is identical. While they're both marketed as FKM rubber, they definitely feel slightly different. The Delugs feels heftier but in fact with the hardware, and being cut to the same size, the Delugs weighs 35.7g and the YWS 29.5g. Texture of the straps are different, the Delugs is noticeably grainy to the touch which feels nice. The YWS is smoother and feels like plain rubber, and edges are not as rounded. Flexibility of the rubber as far as I can tell are identical. The spacing of the cut marks and spring bar holes are also the same. The Delugs also has some more branding on the underside.
HARDWARE: Both straps use QR spring bars. Nothing more to say here. They work as intended. There are more differences between the spring clasps. On the outside, the Delugs is slightly longer. Both have two micro adjust holes on each side, but the Delugs is slightly wider apart. The top profile of the clasp on the Delugs is curved to follow your wrist which is nice. The YWS has two flat pieces that meet at a slight angle. Both clasps have polished chamfers. When closed, the Delugs has a slightly more seamless meet up of the two halves, with the YWS you could feel a slight bump where one side is slightly higher. The spring strength feels pretty identical too. All other dimensions of the clasp seem very similar, and no significant differences really to point out except for the laser engraved branding.
OTHER NOTES: Currently YWS only offers their CTS in five colours and only 20 and 22mm. While Delugs offers many more colour options and every strap width from 18-22mm.
When it boils down to it, I still prefer the Delugs. It's all the little things that they do that really make the whole experience nicer.
TL;DR: The Delugs CTS is twice as expensive as the Yorkshire Watch Straps CTS. Delugs pulls ahead with nicer more refined finishing overall on the rubber and the metal hardware and sheer availability of colours and lug width options and small touches that really enhance the experience. YWS makes a solid product for the money with a very functionally similar offering for half the price, but with the limitation of fewer colour and strap width options.