Imo Eco Lifestyle has much more to offer than SE. Eco Lifestyle has the off the grid gameplay improved with new ways of producing our own energy and collecting water (you can even live from selling the excedents), the rags to reaches gameplay improved with dumpster diving, a new way of setting ecofootprints in your neighbourhoods (green or industrial) that will give a dufferent feel to said neighbourhoods, a way to trash neighbourhoods and lots (debug trash) that also gives a different feel to those neighbourhoods, new skills that can be ways of living (fizzy drinks, candle making and furniture making), new community centers where sims really gather to work in the related skills (i love the market one; it ends up working as a real market where you can sell everything you want or buy from other, without having to wait for the flea market and without it's selling 'restrictions'), 2 new careers and 2 new aspirations, it has apartments, naps (controversial, but i love how they help me give personality to my neighbourhoods; i use them all the time)... and many more!
Snowy escape is nice and beautiful and i don't regret buying it, but it is much more constrained on it's own world. It doesn't feel as an expansion pack. To me it feels more like a game pack: a world with a few activities related to it).