I was crunching the numbers, and the Triplex Pattern Lasgun, despite looking spiffy at first glance, seems to not really be that good (mainly due to the lack of a variable fire setting).
Which makes me think that I must be missing something with the incineration mode, which I thought was supposed to be some kind of heavy-hitting blast. What all that Felling actually does is raise the damage of an average hit to 9.5 as opposed to the M36's 8.5. It is the same damage as the overcharge blast and considerably worse than the overload blast. (Unless you happen to be fighting something with a high Unnatural Toughness and bad armor, i.e., an Ork.)
The precision mode (aka poor man's longlas) is not bad, but the incinerator really seems pointless in most situations, because anything it can do the precision mode can do better -- with the sinple exception of when you have to move and shoot.