I have recently subscribed to Optimus after much research, and I must say I am more than happy. I tried several different materials from different companies. Each has their strength, but something was lacking in every course I tried. Kaplan's verbal is good, but quant is not so much. Manhattan is okay, but somehow the progress from easy to the harder levels is not smooth.
Optimus has a good balance in both the sections, and the difficulty level of problems gradually increase (as per my experience till now). The explanations are really good, though I haven't tried my hand at the tests(full GMAT tests, I mean).
Too early to say, but I think my investment is worth it. Price wise also it makes sense.