If you've bought the other expansion packs, then you're probably going to buy this one anyway, so why bother reading the reviews? :-)
However, if you haven't bought them all and want to cherry-pick the expansions (or you only want one expansion or something), I'd say that this is the one you should get. The "weather" is very well-done and affects your Sims in realistic ways, and of course the weather brings lots of exciting things such as lightning strikes, snowmen, leaf piles and sunburn. You can control the cycle of the seasons for each neighbourhood (and sub-hood thereof), so you can have a perpetually sunny desert neighbourhood, or a snowy wonderland all year round.