Just like Verizon's own prepaid Unlimited 4G data plan, the data is "non prioritized". It will slow down during times of network congestion, but It is not throttled in the traditional sense.
For those of us who live in rural areas where Verizon's network is the only acceptable option, this is the cheapest prepaid deal I've heard of with unlimited 4g data. $55 monthly or $50 monthly with autopay.
3 in one sim card switch kit is just 99 cents. Porting my number was quick and easy.