Hi Diana, the boost 25 is faster. If you experience congestion in your area, it will impact the speeds as it does with your current service.
Here is some information about the modem from our website.
"The Exede WiFi Modem is available as an upgrade for an additional $5 a month in most areas. In some areas, the modem is available with Boost 25 — up to 25 Mbps download speeds. Where it’s available, the higher speeds can be added to your service for as low as $10/month. But remember, you must have the Exede WiFi Modem to get Boost 25 service. " Please call Exede Customer Care at 855.463.9333 or go to the customer portal (MyAccount) if you want to change your plan.