Thats exactly how I felt about it... $140+ for the 306 and my SunSun HW-304b is crushing it for $70 (Amazon Special). As for is it as efficent as the 306, and higher quality; that remains to be seen..
Yeah I would say so, its rated at 525GPH, but its probably more like ~300GPH, which is great. I haven't actually measured it, but the difference I feel coming out of the spray bar which runs the length of the 40 ~ 33in is much strong than the spray bar on the 306 that only ran half the tank ~18in.. The plants are gently swaying in the tank, and you can actually see the filter sucking in the debris through the intake.. With the 306 I would watch debris float around the strainer and then float away back into the tank.