The ICS L85 is a good shout is you want a good solid rifle. It's still a bit on the expensive side however.
I have the G&G L85A2 with ETU and Mossfet, cost around £420, but it's brilliant! although I will note some downsides that I have found using it for the last few months.
1: It's heavy! - its a full metal replica and weighs a good 5kg. with a daniel defence rail and a scope it soon adds up, and when your playing airsoft all day in the heat, or rain it does do a number on your arms (well depends how strong you are, but it's still a heavy gun to use for the whole day)
2: Blowback - its great... when it works. mines broken 3 times in the last 4 games, it simply comes off it's rail, which means you've got to open it up again, re attach it and make sure the worlds smallest alan key screw is tight. It's a pain in the ass tbh. But it's wicked when it works.
3: get a sling - It's a long ol barrel, so if you do get one, make sure to get a 2 or even 3 point sling. 1 pointers aint going to cut it and the gun will either whack you in the nuts or knees... 5kg to the nuts when running isn't fun.
4: it's expensive - for the price you could pick up a second hand HPA M4.
5: wiring - if you get the daniel defence rail (which looks awesome) you wont be able to put your 11.1 lipos in the rail anymore as there simply isn't enough room. You'll have to take it to a tech and get them to extend the wiring a few cm and use a dummy PEQ box. thats the best way of doing it I think, unless there's any super small/thin batteries out there.
Dont get me wrong, I love my L85 because it's the real deal, it looks great, performs great (bar the blowback occasionally) and sounds great too. Get one of these, go to a military surplus shop and you'll be roleplaying as a British soldier in no time. Would recommend the G&G even though I just slated it's flaws, its a great gun and in a crowd of M4's it really stands out. If you could save up and afford one i'd go G&G, if you're not fussed about blowback, go for the ICS - still a brilliant gun but hasn't got the blowback and is a bit more barebones, but works faultlessly. Check out EnglishKiwi on youtube, he also has a great guide on this topic. https://youtu.be/HxRpRZzliRI