Any of the guns you were originally considering on your first post on this thread will be okay. So just go with whatever floats your boat. Since there's not a lot to worry about in those original choices you were considering, what's probably more important is things like magazine capacity, whether the ergonomics suit you, whether you want metal or abs plastic, whether you fancy dressing up as a Yank, a Brit or a German special forces dude, etc.
Other things which might help you decide: G36 mags have that cool ability to clip the mags together in stacks, which means if you go for realistic capacity thirty round mags, then the G36 is a bit more practical for making fast mag changes, since you don't have to drop the spent mag or put it away, although you could of course tape mags together on other weapons 'jungle style', so it's not an exclusive feature, just more neatly achieved. If on the other hand you prefer high capacity mags, that's less of a concern with the M4 or L85, since there isn't much need to rapidly change a high capacity mag that often. The L85 on the other hand, like most bullpup designs, is not known for facilitating fast mag changes, so is a slightly worse choice if you do use realistic capacity magazines, nor is the L85 as suited to switching to firing left handed as a G36 or an M4, both of which have some ambidextrous features more suited to lefties. Most M4s have a collapsible five position stock, which means it is easy to get it sitting in your shoulder exactly right, and it can be made a bit shorter for the tight confines of CQB. With an airsoft G36, theoretically you could fold the stock and fire it, but if you favour realism, the real G36, whilst it can indeed be fired with the stock folded, is not intended to be used that way, since firing a real G36 with the stock folded causes internal damage to it, thus its folding stock is only really intended for storage and to facilitate getting in and out of helicopters and APCs. but of course if you don't worry about realism, then it's not a concern.
All three have plenty of rails, or can have them added, so they're all suited to putting scopes, lasers, tac lights, grenade launchers etc on them, although again, you'll find the M4 is easier to faff about with in that regard. The G36 is largely made from polymer in real life, so a plastic airsoft one actually looks and feels like the real thing more than a plastic M4 or L85 would, although to be fair, the novelty of having a real metal weapon is largely just that, a novelty, and makes little practical difference in airsoft unless you are the kind of person who likes to dramatically dive for cover, in which case a metal weapon might stand up to things a bit better.
The M4 is the most ubiquitous of the three, which means it suits a lot of loadouts and nationalities if you want to dress up in realistic camouflage, as it is used by several nation's armies, many special forces units, and a lot of swat teams and police forces, whereas the L85 is only used by the British Army, the Jamaican Defence Force and odd units around the world such as the Columbian Drug Squad, so it's less suited to a lot of different loadouts, but then again, if you really fancy dressing up like a Brit in Helmand Province, then it might be your ideal choice. The G36 is of course in a bit more widespread use than the L85, but it comes nowhere near the M4 in that respect, which aside from being popular with many legit forces, is far more likely to be a rebel or terrorist weapon than either the G36 or the L85, although if that notion floats your boat, then an AK of some description would be a more suitable choice of course, as well as opening up the possibility of dressing up as any one of a number of Eastern European or Middle Eastern military force dudes. You'll find a lot of us on here have Commie leanings (or at least we do when it comes to buying assault rifles :lol: ).
There are many other little things like that which might suit you or annoy you, such as the M4's fire selector easily able to be knocked into another position when on a sling rubbing against you, or the L85 being the best one for lying prone owing to its bullpup design, which also gives it the longest barrel too, the AK on the other hand, is fairly difficult to go prone with owing to that long ass mag digging into the ground and preventing you from really digging in, it is however, ideal for firing into the air whilst yelling in Arabic and will definitely legitimise your keffeyah.
Thinking about all that stuff might help you toward a decision.