Buy an AEG for your first gun. If you're in low price range ($200 - $400), look into G&G and King Arms, they make great starters. If into something a little better to begin with grab a VFC ($500 - $700). If price is no object then Systema is the best gun on the market. Functionality, feel, distance, accuracy, consistency, etc. They go from (1,500 - $2,500). Systema's will eventually require a motor rewind when it fails, usually anywhere from 3 months to 2 years, but 6 months to a year is average. Once it's rewound it's usually bulletproof. Getting the hop-up mod makes the best hopup better.

GBBRs are fun for the little bang or snap they make, along with the bit of kick you get when the bolt cycles. A well tuned GBBR can be very accurate, but they don't perform well when it's hot or cold, and usually cause repetitive headaches. Considering their balance of reliability and function versus maintenance and mood swings, they aren't great for a first gun.

As for realism, the kick and sound of a GBBR is best. For feel, weight and exact one to one compatibility, then Systema PTW is best. A good balance of realism is good, but accuracy, consistency and reliability come first.

Would definitely recommend G&G as a weapon that is decently priced, performs pretty much above par out of the box, and is a breeze to work on later if you so choose to

+1

I have a grouping at 260ft that would disagree lol
7511s of 2012 were more likely to fail in the first 500 rounds
The new KUMI 7511s are much better
KUMI 490s are also good
But ultimately the inferior motor is the price you pay for all the other benefits of the gun

VFC is the one of the best brands in my opinion, I own 3 and they run great.

OP, you are limited only by your budget.
If you don't care about your budget, get a Systema.
Next step down from that depends on whether you plan on upgrading it.
If you are not, VFC or KWA as both offer nice externals and solid internals.
If you are upgrading, VFC or G&P both have extremely good externals as base guns for you to upgrade the internals (KWA is proprietary, so don't get that).
If you can't afford those, King Arms is the standard go-to full metal M4. Classic Army and G&G also offer some good pieces.

Hop up disagrees after its not stock lol. But I guess this thread can go a LOT of places if you assume every gun has been built up.

pfffff who the hell keeps a stock barrel group when they want any sort of range or accuracy?
cheapest and best upgrade for any gun

I Currenly own a KJW P226 first time i fired it the hammer rotor broke

That's rare. I have two KJWs, one a P229. Absolutely glorious.
KJW and We both have readily available replacement and upgrade parts, many of which are cross-compatible, depending on the platform.
A friend has a We M4, an older closed bolt one. It's fantastic.

Ghk m4 should be the best skirmishable gbbr m4 out of the box. The magazine gas system is made out of magic!
Else, AEG I'd say vfc as well... it looks better and more accurate than g&ps and shoots just as good. Very accurate guns but if you are wanting to upgrade fps and rof, you might run into some problems. G&ps are easier to upgrade in that aspect. Usually I just run VFC aeg with an upgraded tightbore barrel and hop bucking and leave the rest as stock till it breaks.

Ehh, well my Kjw P226 Valve knocker/ firing pin broke. Then it was the hammer chasis and then It was the barrel. This was all within a period of 2 years. It was a great pistol but It did not handle very well in the cold and you can get around 30- 40 shots per fill.

Eesh, that sucks! I've had no breakages. One minor hiccup with the trigger bar I'm trying to figure out, but otherwise it's a joy.

I went in to get it repaired for $50 I don't want to have to do that again. I just don't want to take apart my guns myself until I'm confident in my ability to repair it