I have used the $20 model that Harbor Freight has, and it worked great.
What is so different about this Bosch that it costs 5x more?
More power/torque?? Longer lasting?? Different rpm??
Is the Harbor Freight one 60Hz and the Bosch 120Hz or 240Hz??
I've bought 10+ power tools from Bosch and all have preformed excellently... I've bought maybe 8 tools from HF and 2 went back to HF after the first use, and only work moderately well. If you don't see yourself using a tool often or need it for a one-off project by all means save the money and go HF, but if you want straight lines time after time, and ample power, go Bosch/Milwaukee/Dewalt, etc...