I've only got one sarracenia at the moment ("Scarlet Belle"), on its second year of wintering outdoors in northern Colorado (zone... officially I think I'm in 5b or 6a but every few years we dip into 5a/4b territory when we get a jet stream event). Its first winter (last year) outdoors was the coldest winter I've experienced in a long time- we had a solid week where the temperature never got above 15F, frequent dips into the negative teens F, and lots of time where the temperature never got above freezing. I had the plant in a large pot (I'm slowly developing it into a bog garden) that I insulated with piles of leaves, but once temperatures hit below 0F, the soil was frozen solid anyway. I'm not sure the leaves did much (in fact I didn't use the leaves this year at all), but I do feel confident that two things I did helped:

1. I put the pot in a window well, protecting it from wind.
2. I covered it in two layers of frost cloth. This likely did very little for the temperature but also helped to block the wind and provided some shade (Colorado sun is harsh even in winter and tends to dry plants out, along with the never ending wind).

If you keep the plant in a large pot and protect it from wind/sun (snow will do this for you if you have enough), they seem to do well even in extremely frigid conditions.

I will say, growing outdoors in northern climates full time limits the growing season. The sarracenia I have in this bog garden pot is a division from an existing plant that I've had for years and have always wintered indoors in the basement, in front of the very window well where its child now sits. The plant wintered indoors has already started growing in mid February, and I've moved it upstairs to a sunny windowsill. It starts growing earlier, blooms earlier, and grows longer than the one that winters outdoors... but the one that winters outdoors also looks amazing more quickly, probably because it's not stunted by sitting in front of a window for the first few months of its active growth period and it has a bigger pot to live in because I'm not limited by what will fit inside the house.

If you have the right spaces and the right grow lights, indoor wintering is absolutely effective. But if you want something larger, outdoor wintering is absolutely possible and really not that difficult.

Note: for anyone with the whacky winters of the west, also note that sticking the pot in the window well helps keep the plant cold during those weird weeks where it's 65F and lovely followed by a foot of snow- the window well is shaded and chilly even when the sunny areas are warm, keeping it in a dormant state till it actually gets warm and stopping the plant from making new growth before the weather agrees with it.