Since a match-up thread for Roy vs. Ike was recently created, I'm going to post my thoughts of it here.
A fun match-up, in my opinion. I'll start by comparing their attributes from a Roy player's perspective. ^-^
+ Roy has better ground and possibly better aerial mobility than Ike
+ Many of Roy's attacks, both in air and on ground, have faster start-up and less ending lag.
+ Roy has a stronger Counter than Ike; 1.35x damage multiplier as opposed to 1.2x.
+ Blazer is an amazing OoS kill move.
* Both have a vertical KO throw at around 170% - 185%; both will kill earlier with rage.
* Both characters' recoveries are linear, predictable, and gimpable.
- Many of Ike's attacks, both in air and on ground, out-range Roy's; Roy needs to close the distance to maximize his damage output.
- Roy lacks SH auto-cancelled aerials, compared to Ike.
- Roy is a fast faller, making him highly susceptible to Ike's throw combos.
- Roy is lighter than Ike; the latter can survive longer and make better use of rage.
Both characters can combo and Counter themselves to death. They both also benefit from rage with their already powerful attacks. Obviously, for Ike, he would want to keep his distance and space his aerials to stay out of Roy's sweet-spots; this means an Ike can play the match-up similarly to how a Marth would. Like against other characters, being able to combo out of D-throw from low to KO percents is critical for Roy. Roy's best aerial approach option is to use N-airs as it has the least landing lag of his aerials; for ground approaches, probably Double-Edge Dance. Roy can use his superior mobility and faster aerials to weave in back and forth around Ike. Ike would have to use his smashes more sparingly due to Roy's powerful Counter.
On the other hand, Ike has become more menacing as of the 1.0.8. update. He now has a Dash Attack that can KO many characters, like Roy, near ledges at around 100% - 110% without proper DI, landing lag reductions to his aerials, hitbox fixes, and more. Ike's U-throw to F-air is a kill confirm on Roy near the ledge at around 110% to 115%.
With good reads on both sides, this match could go either way. Do correct me if I'm wrong with anything, just in case I end up spreading misinformation.