As stated in my explanation, the big difference is being able to select the location of the string inverter. For instance, I can put the string inverter indoor near an AC unit. I can also install it in a nice enclosure (outdoor) and give it some sort of active cooling in the summer. I am not an electrical engineer (bioengineering and computer science), but this seems to be the optimal solution since the inverter itself is where most of the loss stems from.
I am not saying that the enphase solution is bad, its just not as advantageous as you seem to claim although i will admit that installation is indeed easier. Maximizers (or optimizers) seem to be a nice middle ground that offers the advantages of micros while letting you chose whatever inverter you want (true for tigo at least). I really dont think there is any advantage to micros over string in terms of conversion efficiency once you do the math except for the 1 point made above, being able to choose where to place the string inverter is an advantage. I am probably going to place mine in one of the spare bedrooms opposite an AC vent.
You know... after nearly 10 years monitoring yahoo forums I am always amazed by the number of idiots in the investment world and how blind they can be.
Beans on the right track and there is nothing wrong with being critical (I am extremely critical of comapnies I invest in and believe me, I have more money than you do). Here is a reality check. I live in San Diego btw. Over the last month I have collected about 2 dozen solar quotes for my various properties from about a dozen different contractors from big guys like solarcity to small electrical contractors. Want to know how many recommended micro-inverters? The answer is 1. Want to know how many quoted me optimizers? 8. I had 2 or 3 quotes for simple string systems.
Reality hurts. But what Enphase should be more worried about is their finances, specifically debt.
After all that time spent with bids, I decided to install it myself and pocket the $20k (per install). I bought panels from ebay and warehouse in LA ($0.75/w for 315w 16.5% mono's including freight). I decided to go with Tigo optimizers and a Solis inverter. 30x Tigo optimizer ran me $1650 with shipping. The 2x 5kw Solis inverters were about $2700 total. So the total was about $4350.
It would have cost almost the same to go with c250's (about $4300 shipped) but everything I read online has stated that the micros drop to around 80%-85% efficiency when the under panel temperature rises above 100 degrees (this happens a lot in San Diego)... I have yet to hear anyone say this is not true in real world application and if it is true, it makes them on par with cheap $100 1000kw no-name grid tie inverters from China.... Optimizers simply dont have this problem and a string inverter can easily be cooled to maintain highest efficiency... there is no easy way to cool micros.