I bought the sabre the first day it came out, and yes, I can say that it is worth it. Plus, now that recycling is out, it shouldn't take as much work to get a good amount of money for the sabre. I find it good for melee sparring, since it is fast and does (I believe 8 damage). It also has uses at planets.

Say you're at Spring, and you're almost about to win. You can sit at Base Two and you can just use your sabre to block the bullets sent by them in an attemp to attack the people at Base Two before their time runs out. It will save you health and time.

For non 2D bases, it also has some uses. When at a base and someone comes to attack, they'll most likely get to the opposite side of the base and start shooting at you. You can just use your sabre to deflect their bullets and launch them backwards at them. I've actually killed someone just by deflecting their bullets. Although, you can block their bullets and rush them by swinging you sabre at them for 8 damage every hit.

So yeah, I find it worth it.