What are in your opinion Ike's best customs? I like the upgraded Eruption, both Side B customs, Aether Drive and Smash Counter most personally.
Since Ike relies on both his side and upB for recovery, the combination of the two changes the style of recovery and how Ike responds to opponents offstage. Recovery, handling offstage, and offensive strengths often change depending on which side and up specials are used. This is why when looking at which upB is used, you have to look at the sideB as well. Many Ike mains just don't like the style difference from offstage play than what they're used to with default aether.
Close combat side B may go farther than the default fully charged before the extra momentum kicks in, but it doesn't go very far at all uncharged. This makes it so that it has somewhat poor synergy with aether wave up B recovery-wise (even though they're decent offensively).
Close combat has much better synergy with aether drive, while the default side B has better synergy with aether wave. Default aether is good with both of them. The super armor side B can only be used with aether drive to remain viable.
Aether drive is good since it lets you play without having to worry as much about your double jump. Aether wave is fast goes nearly as high as the default, and launches an reflectable projectile that deals shield damage, but it doesn't have that great of a synergy with close combat. Both aether wave and aether drive can stage spike easily and abuse ledge vulnerability. Default aether has the best versatility and reverse aether is still decent.
Close combat has more endlag and doesn't deal as much damage, making it tougher to use offensively. It seems best suited for landing traps to extend strings or to force respect from opponents who keep throwing out aerials. Default side B can build up some kill power fully charged and has a more versatile recovery. Its biggest problem is that it generally does poor damage and misses all the time if it triggers vs opponents above and below him. The super armor side B is purely an up close punisher, kind of like counter. Unfortunately, super armor only triggers once it begins to charge on the ground after 18 frames or so. The super armor doesn't kick in early enough or in the air, so I see it as best used as an alternative to eruption near the edge, or as a pseudo followup after a throw or aerial if you jump right in the opponent's face.
All 3 eruptions are useful. Eruption 1 charges quickly. Tempest is good for disruption and gimps, charges the quickest, and lingers the most when fully charged. Eruption 3 has more end lag and doesn't kill unless charged, but it is the easiest to hit with long lasting hitboxes and a purely vertical knockback.
Sometimes, tempest feels best since you can blow people away. Sometimes, eruption 3 is best because if you're hitting people with tempest, you'd be hitting them with a powerful eruption in the same situation. Sometimes, eruption1 is best when you only throw them offstage and have a chance to hit them with a kill move right off the bat vs. a predictable recovery. Eruption can hit any ledgegrab attempt from below with 5-7 frames of leeway, making the default quite decent with good timing (furious eruption is 11-16 and tempest is 15-23 frames of lingering hitboxes depending on the charge)
Counter1 is decent vs recoveries and smash attacks, but bad vs quick moves. Paralyzing counter is good vs quick moves and good vs recoveries (because it attacks faster), but bad against smash attacks (rewards-wise) and is harder to pull off in general. Smash counter is great against smash attacks, but terrible against everything else.