I rather like them..... and frequently field a pair of these. First, they are relatively inexpensive, compared to other mediums...... and, as has been noted..... they just don't seem to get targeted much. I find that most people assume that they are not that dangerous, and just kind of ignore them.... which lets you do all kinds of sneaky things with them. I like to pair them with heavy slow assaults, like Awesomes, or Stalkers..... where they can react to backstabbers, and still add their firepower to the big boy. Trust me, and Atlas, supported by two of these, is a PAIN to deal with.......especially in 3025.
Sadly, the Crab's higher tech variants do not add enough --- and while the 27b scoffs at heat, and the 27sl has great maneuverability.....the two concepts did not seem to be considered in concert.... as in, a 27b with 13 or 14 double heat sinks and jump jets.... which would have been a strong contender.
Now, a version of the 30, replacing the C3i with additional double heat would be a strong contender in later eras.... as 2 ERPPC's and the heat to use them, makes for a great direct support design.
The biggest thing to remember, with the Crab, is that it's a team player..... it's really the laser version of a Whitworth.... it does it's job of supporting it's lance, and it does it well..... but will always get ignored over other, flashier, designs. In the end, you can use it like a trooper, and it will easily match an Enforcer.... especially the 3025 versions of both designs..... making it a great add for a line unit, and while it doesn't get the extra 2 points of damage that the Enforcer gets with the AC... it also doesn't run out of ammo .....while in close terrain, those large lasers have the damage to almost match PPC's..... and the Crab can keep up a good fire rate.... usually better than PPC toting designs..... which in the 3025 era, will allow it to rack up higher damage, over time.
It's final advantage is that most people unconsciously ignore it.... and sometimes, that's the best thing going.
Nahuris