The major drawback would be the real body closeness. Internet is a great tool, and remote toys helps. But what you both will miss most, would be the real contact :) 
There's where you have to "work" most. 

The biggest downside of LDR is the lack of physical contact, the personal connection that a lot feel to be a staple of the relationship and in a lot of ways it is. The emotions and way of dealing with them play the main role here.. I guess that's the worst. You need to deal with them all by yourself until you see that other person. Could be away for long but words and keeping in touch make a big difference- as well as respecting the situation and having a lot of trust. 

Not being able to give a simple hug when someone needs it. That's what I think is the hardest part. 

Schedules.  I'll agree that long distance also doesn't supply the same emotive response as physical contact, but the most difficult part from my experience is simply trying to keep schedules in synch in different time zones.  Each lover has additional interruptions, with their own urgencies, vying for time and attention.  It takes a lot of commitment to be able to carve out time to keep exciting each other.

Lack of intimacy and everything it could lead to. But Lovense is working hard to fix this issue once and for all :)

my dick

wonderful!!!  

We used to fuck so much but distance toys just aren’t doing it for us. 

The lack of physical contact, even a hug would be vertly special right now.

My C*** when she's Gone :`(