Well the Ultimate Question for X Pulse lasers isnt are the worth taking but rather are they worth taking over existing technology.
The ER PPC and standard Medium Laser are my choices for energy weapons.
Range is crucial as it both gives you a maximum attack range, but also alters your weapons' short/medium/long range.
The ER PPC compared to the Large X Pulse Laser have almost identical stats. the Large Pulse is better at shorter ranges, especially 1-5. It loses when you get to 16-23 as the X Pulse cant fire that far.
Depending on your build and what you are facing might be a major problem. Large X Pulse Lasers can be AWESOME but at the same time its a "big gun" due to its weight and heat sinks requirements. a lighter unit might have 1 and a larger one can have 2 reasonably. On a lighter mech it can be quite good but a slower mech you might be constantly out-ranged. Its a good idea to have some LRMs or an LBX-5 to respond.
However ultimately you really do want clan-tech. Increasing the range and decreasing the heat generated by Clan Large Pulse lasers is just awesome.