Why is the A320neo considerably ahead of B737Max?
I certainly would not say that the 737 MAX is "losing heavily" to the A320neo. The A320neo is entering service in the next couple of months (October 2015.) The 737 MAX isn't entering service for another 2 years (2017.) I don't think many aircraft manufacturers would be upset with having 2,727 orders for an aircraft that is still 2 years from even entering service. It should further be noted that the A320neo was right around the same total when it was 2 years from entering service.

Some additional factors that come into play:


The A320 line tends to be more popular in the low-budget Asian market, which is growing significantly right now.
The U.S. Dollar is currently relatively strong compared to the Euro, due to lots of economic problems in the Eurozone. This means that products exported by European manufacturers are relatively cheaper than products exported by American manufacturers compared to their usual price difference. Obviously, that's an advantage for Airbus, as it means that it's cheaper than normal right now for customers to buy Airbus vs. buying Boeing. This is, again, especially important to the cost-sensitive low-budget markets.
Airbus' Chinese assembly line allows them to make A320s for the Asian market quite a bit cheaper than Boeing can make 737s for that market, due to the major differences in labor costs.