If you GA'd with:
~$8 .com addresses, N real inboxes, free whois guard and a top notch DNS record API.
That's a compelling offer and I'd very likely switch from namesilo if that were the case.
To be honest, anything less and I'd stay with namesilo because the 15 minute timer can be worked around by using my web host's name servers (digitalocean pushes updates in a few seconds). I couldn't live without either email forwarding or a real inbox.