2017, which platform to choose between MetaTrader 4 and 5?

Hello,
We are in October 2017.
If I want to develop from zero new EAs, what platform to choose between MetaTrader 4 and MetaTrader 5, so which language to choose MQL4 or MQL5?
Please detail your choice.
My opinion :
In the past I did not ask myself, because the choice of brokers offering MetaTrader 5 platform was very limited.
Today it seems less and less true.
Hence my hesitation.
Apart from the greater choice of brokers offering the MetaTrader 4 Platform as the MetaTrader 5 Platform (which should continue to decline over time), is there another reason to choose MQL4 instead of MQL5?
The idea would be to develop in MQL5, and if I really want to open an account at a broker with only offer MetaTrader 4, make my MQL5 code to MQL4 compatible.
Regards,

I persomally prefer MQL5 and I fully moved my developing from MQL4 to MQL5 about 9 moths ago.
First there are actual tick history built in. This means tou don't have to download it and hack MT4 to load it. This is useful for strategy testing and also can be used to build tick based indicators.
2. MQ recently introduced custom symbols that allow loading of custom data and test strategies on ot.
3. The performance is much faster for both indicators and EA's.
4. There are much more events. More advanced trade management.
5. MT5 separated orders from deals and positions allowimg full netting functionality that is not more limited the hedging account and wven allows using opposite limits to take partial profits, which you can't do in MT4 or hedging account.

*** If you plan to write MQL4 compatile code on MQL5 , I'd stay on MQL4, since you lose all the benefits to comparibility.

I prefer MQL5, however, the brokers who offer it are limited and typically charge a lot more in trading fees.

There aren't many brokers that offer MT5 and who knows whey they'll actually start offering it. Another thing is that MT5 is not bug free. MT5 has problems. It makes sense to develop for MT4 due to its popularity, technical support, and solutions from developers.