Mantra Comp...
I would seriously consider it. I have had two Klein bikes. My current is the one specified above. The first was a Pulse Comp. I have nothing but great things to say about Klein. Their frame quality and geometry are first class. I have rode some very nice machines that are more “advanced”, and some which cost double, but I keep gravitating back to Kleins.
Worse case if you don’t like it you can throw it on ebay. There is a Mantra frame selling for almost that right now, and a full bike for almost $600.
Try a Klein. You will not regret it.