I agree with trekking bars for converting a MTB for cheap, but going for drops otherwise.
My major gripe with my trekking bars is that my main hand position is on the sides of the bars (similar to being on the hoods). This place my hands away from the shifters/brakes.
Riding on the top and sliding forward to the hoods on a drop bar is much easier/faster/natural than riding on the sides of the trekking bars and sliding back when need be.
The trekking bars have a slight advantage in stop and go situations as I can sit up higher and have my hands on the brakes, but the drops win overall.