It's actually getting uncommon for mobile unlimited data plans in Sweden again.

Almost all major carriers are now trying to squeeze out some cash for the mobile data plans. Some are succeeding very well, usually by packaging up calls, texts and a mobile data plan with 1-3GB/month for a fixed fee. {99, 149, 249, 299}SEK/month.

The 3G data network is very spotty in Stockholm, throughput-wise. I assume it's very congested. I have no idea about the 4G/LTE data network though.

Of course some operators have it as an option - but it's not standard here, yet.