Average data rates on EE 4G in Manchester are 12mbps, taken directly from the mouths of the EE staff and seen in-store on their demonstration phones.
Three 3G is around 11mbps, but there is something in 4G phones called DC-HSPA+. This bridges two 3G connections, giving you double the data rate and incurs no extra cost. Notice how I said 10-20mbps?
If you have DC-HSPA+ on Three using a 4G phone you will see average connection speeds nearly double (22mbps) the average EE 4G speed (12mbps) and over half (22mbps) the theoretical maximum speed (40mbps) of the current LTE implementation. On a standard HSPA+ 3G phone you will see a speed slightly slower (11mbps) than the EE 4G average (12mbps).
So yes, 4G is probably a little faster given ideal conditions, but it's fairly similar under average conditions. Then consider that you are paying over £50 a month for 8GB of data (measly), compared to under £25 for unlimited data (unlimited).
As I said, EE 4G is pretty poor really.