VPN and tablo use

Will using a vpn slow down internet or inferior with Tablo ???

Do you mean running a VPN client on your router which the Tablo is connected to?

Yes and what would be a good one

1, why do you want to run a VPN on your router? This will likely cause problems with the Tablo.

2, what is the make and model of your router? This is not an easy task for many routers to run well, it usually drastically slows down the download speed and upload speed due to the encryption being CPU heavy.