I rarely deep wade in winter, but sometimes need to cross a river to get access to a swim when lure fishing for pike or trotting for grayling. I use chest waders for this reason , and the bonus is being able to sit down anywhere you want , which is important when your back is aching after an hour or so of standing up. Normal chest - or waist or thigh - waders can get damn cold in winter unless you are moving around , which I am doing constantly with both styles. Neoprenes are much warmer, but can cook you on a warm day , and can be more awkward to walk in .
I use Vass breathable stocking foot chest waders for spring and summer fly fishing , and they are the only breathables I have owned which withstand my abuse ( overgrown banks, brambles , my innate clumsiness etc) . Others have leaked within weeks or months . Great in mild weather, but parky in the cold. I use these with studded wading boots . My PVC chest waders are also Vass , with studded soles and they are comfy and relatively warm as long as I move regularly - I've grayling fished in minus 8C and survived . I buy at least one size too big, for ease of putting on and taking off , and to allow extra socks.
For all other fishing I wear Aigle neoprene wellies , which I find good to walk in and much warmer than moonboots etc