Difference between 4G, LTE, and HSPA+

No major carrier offers anything close to 4G speeds. LTE is as close as it gets.

Peaks in absolute optimal conditions:
4G = 1Gbit/s
LTE = 300Mbit/s
HSPA+ = 168Mbit/s

The big difference between LTE and HSPA is that LTE provides 5ms latency where HSPA is either 25ms or 50ms can't really find solid validation.