Like night and day for many reasons. A group 27 high end is 105 ahr on the easy 20 hour rate and weighs 57 lbs.
My 100 ahr LiFePO4 cells is derived from a brutal 1 hour rate and weighs 31 lbs.
If the group 27 got its ahr rating from a 1 hour test (pulling 100 amps for 1 hour instead of 5 amps for 20 hours) it would be empty in 20 minutes due to Peukert effect and deliver 32 ahr.
Now move on to usable ahr, lead 50% DOD, LiFePO4 80% DOD. If the load is 100 amps, you have 10 minutes of run time on the lead acid whereas you would have 48 minutes run time on the battery that weighs 1/2 as much.
Cycle life, 400 cycles group 27, 2000 cycles LiFePO4.
Voltage sag, a lot at high current draw for LA, nil for lithium.