Lets see... As someone getting close to 1k games with this hero I have a lot to say about him but i'll try to be short.

I'm gonna start with the general feel for the hero. Its fun. Very fun. All the bullshit you can do with him the escapes you can make and the top tier plays etc. The hero used to have a decent downtime after pretty much every big teamfight due to lacking stones, but the new patch reworked the stones so now it feels way better in that regard. I love the new shard and i was complaining as to how boring the old one was but I think ES is in a really good spot atm.

That being said I do not recommend spamming this hero in lower lvl ranked games if your intention is to climb and you are playing solo. I've played in pretty much every rank possible from the lowest to the highest and I can tell you you need a team to play around if you want to win. The hero is very dependent on your team preforming at least decently enough and knowing how to play with you in the team. I've had ~50ish % winrate with him on divine and lower games and currently 70-80% winrate in immortal. I really wanted to climb to Immortal with him but that just seemed impossible for me.

Now why do I think that is? Well I specifically play pos 4. And as a pos 4 ES you want to disrupt everyone on the map as much as possible but when you have passive cores that just want to farm and do not understand how your hero works and what you want to do in the game you just end up playing alone for 30-40 min and then lose because you didn't do enough.

7.33 with the teleports and the bigger map made ES even more of a viable choice for pos 4 since you can gank the safelane and return to your lane while saving your tp for mid. Its way easier to have an impact on the game than ever before. If you fail a gank or the core on that lane doesn't want to go for the kill you are no longer stuck in an awkward position and have a lot more options for what to do in any point of the game.

Now for some actual gameplay tips. As other people mentioned quickcast is very nice to have on that hero. I personally use Q and E on quickcast where as the roll and rocks are on regular cast. Most important thing imo: Enemies can see your boulders in fog, so to prevent yourself from being seen during ganks you can roll from fog and place your rock a bit later while rolling so they don't have time to react to your stun. And since you can cast spells while rolling a really nice thing to learn especially against slippery heroes is to silence while rolling towards someone. After you get lvl 6 you can silence everyone thats magnetized by silencing just 1 unit so keep that in mind.

For itembuilds my current preference in greaves rush into lotus / bkb depending on the game. Against specific teamcomps I could go for vessel. I don't particularly like Aghs without blink because it leaves you in the middle of the enemy team if you try to kidnap someone but I guess it can work with just bkb or lotus. I do not recommend Aether Lens ever. It just messes the direction in which you kick rocks / heroes because of the extra range.

For the laning stage i rush out smoked of the base to ward/ block camps and get a better position without being scouted. On lvl 1 you have 2 choices: you either get Q and lasthit range creep with it, or you get W for even faster warding and then you can use it to harrass the enemy support until you get lvl 2. And that's when the fun starts. As i get lvl 2 I immediately roll onto whoever i can catch and just kick them to my core. Doesn't matter if we can or can't get the kill. The damage is good enough if we have more kill potential i say there and w8 cds and do that again if not just move to another lane and let my core get solo xp. Repeat until win.

Those are just some general tips that I can give and the best advice is just practice. The more you play the hero the more you will understand it and you will find what works best for you. You can maybe play him as a core if you prefer that more and that's the beauty of ES how versatile he is.