There are 2 other lower cost ciculators out there, both at $199. The Sansaire and The Anova. I went with an Anova, and love it. Cheaper than the Nomiku and Anova's been on of the leading brands of lab grade circulators for decades. I've heard some dodgey things about the Sansaire, even discounting their legal troubles and shipping problems. Apparently there are build quality issues. Anova has a kick starter for a new cheaper circulator running right now as well
Other than that I'm curious as to why your heating the water before you add it to the bath, and adding additional insulation. These things are designed to heat the water from tap temperature, so its unnecessary to add hot water to them. Unless your vastly exceeding the max volume (22 liters on the Anova, similar for the Nomiku if I remember right) it shouldn't take more than 15-20 minutes to hit temperature, and no additional insulation should be required. Adding warm or hot water (below your cooking temp) speeds that up considerably. But I don't see a point in trying to add water that's at your cooking temp when the thing is a heater. Anyone adding boiling water to the bath to up the temperature runs the risk of overshooting their selected temperature, and since these things can only heat not cool the water, you'd have to wait for the temp to come down naturally which can take waaaay longer than heating it up depending on how far you have to go..
In terms of your tough steak, it takes a while. I did a couple large chuck steaks at 130 for 28 hours and it worked great. Mid rare steak with the texture of pot roast. Many recipes for tough cuts call for even longer, 48-72 hours or so size dependant. You might have been running at too high a temp, or not let it run long enough, give it another shot cause its a neat trick.