From what i understand the one XL is the international version of the one X. The XL uses a snapdragon dual core 1.5ghz and the One X uses a Nvidia tegra 3 Quad core @ 1.5 ghz. The One XL has 16mb or storage where as the One X has 32mb storage. However the only upperhand that the One XL has is the LTE compatibility... Other than that its been proven the battery life on the One X is superior to the One XL.
Heres a vid of the 2 being compared over multiple benchmarks..
Heres also another in depth comparison of features...
HTC One XL (S4): 4117 native, 161 Java
HTC One X (Tegra 3): 9997 native, 311 Java
HTC One XL (S4): 9531
HTC One X (Tegra 3: 13,719
HTC One XL (S4): 6693
HTC One X (Tegra 3): 10788
HTC One XL (S4): 4668
HTC One X (Tegra 3): 4780
HTC One XL (S4): 3002/2669
HTC One X (Tegra 3): 4453/2697
HTC One XL (S4): 5669 50fps
HTC One X (Tegra 3): 7325 65fps
As you can see the One X is clearly the winner and the next phone i will be buying.