I had a buddy that used a Mikrotik router for years. He couldn't shop at Newegg because his router "optimized" his MTU and Newegg blocked connections with non-standard MTU sizes.
That's a Newegg misconfiguration. If they received a packet with an MTU they thought too long, they should have responded with ICMP Fragmentation Needed.
Mikrotik sometimes do things differntly to how you might expect[0]… though that was how I found out about them, and have been happily managing a hEX lite for a while now.
This is definitely a bug (a 'value of out range' for prepend > 255 should have at least been emitted), but IOS devices crashing because of it is noone but Cisco's fault. And then, not having a 'filter out if AS path > 64' config line while being a transit provider is just careless.
I've had a Mikrotik router for a few years now, and have absolutely no problem with Newegg at all... perhaps one or the other has fixed things since your friend had trouble?
It's fixed for the most part as of 1.2. There also the MemGraph mod that allows you to give more memory to the game so the GC doesn't fire off as much.