I've played a few games so far with Environmental Testing and I would say it has exceeded my expectations. The reason is simply that one for 6 is very strong. Almost no other economy cards come close to this exchange rate, except for a really big Bravado or drip cards like Rezeki that pay out over many turns.
This is of course the best case scenario for ET, but is pretty easy if you get the timing right. Self-modifying Code, Simulchip, Rezeki and Misdirection earns you your four programs/hardware. As does SMC, Simulchip, search for an icebreaker then reinstall SMC.
It really is not that difficult to hit this point, so it is possible to get explosive amounts of money pretty quickly, all for a down payment of 3. ET has been compared to Technical Writer, which while having much less overhead (0 install cost) it builds up much more slowly, and requires a second click to use.
I think this card may be strong enough to be worth importing into Az or other hardware-heavy Crims that install a lot of Boomerangs. If your typical rig uses >4 hardware/programs, consider it!