I personally would say bi colour. I looked at turtledove PM and whilst it’s a beautiful colour, for me there was still a concerns of colour transfer (love me some jeans). I originally opted for Empriente Noir (2 years ago) and I really loved (and still love) that piece. I would look at Turtledove every so often, but I couldn’t pull the trigger because of colour transfer concern.
Last week I have added a bi colour PM (black and cream) to my collection and I couldn’t be happier. For me it covers the need for both black and light/cream colour bags without been limited on my wardrobe or worried about potential colour transfer. Initially I was somewhat worried bi colour PM could be too ”loud” of a bag for me (I am a very casual dresser), but I am happy to report it hasn’t been the case. It goes with majority of my outfits (light and/or dark) without been too overwhelming (I find monogram canvas more “loud” despite loving it to bits). It does have a “pizzazz”, but just enough to remain classy and wearable (but of course its a matter of personal opinion). I am glad I still have my Noir Empriente PM as I still use it in bad weather (rain and snow) but should I have to choose one now, I would definitely go with bi colour one. Hope this helps and good luck deciding!