Okay so I don't come off as a poopy head for not even adding input, I'll add input
Like wintropy said ROB is a floaty character with a large hurtbox, which isn't a very favourable combination. You can attack out of Robo Burner to compensate for the lack of a hitbox, but it isn't as versatile as it was in Brawl
UTilt has nice vertical range and setup hits, but it has noticeable startup. FTilt is quick, but has less-than-stellar range. DTilt is REALLY quick, and it has pretty OK range. FSmash has EXCELLENT range, but it has abysmal WFT-tier startup. I think DSmash is still pretty solid.
UAir is really good, but aside from that, ROB lacks aerials that can reliably KO. NAir and FAir are pretty weak, and BAir has significant startup. Idk about DAir so I won't comment on it.
ROB's specials are pretty solid though. Gyro is a lot easier to get control of now, and Z-dropped Gyros are a nice shenanigan. Arm Rotor has gotten a sweet buff, but it still suffers from the fact that it's really punishable and will invariably gimp you if you accidentally use it offstage, which will invariably happen ;_; Laser is really good in it's lower stages because of how quickly it recharges, but the fully charged version's range is lacking imo
Of course, most of this stuff is comparing against Brawl ROB, who I mained, so I'm not the best of players for this. I was adding my two cents but look for better players' opinions in that thread I linked. Just search the thread to see what people have already said, and post in it too to get more opinions.