At the moment both JUNO/ROWAN and OSMO/ROWAN pool have large bonus APY (See below for APY at the time of writing). Please note this is APY and NOT APR. Difference is explained here. The bonus pool on JUNO will end soon on 10/22 so I think there will be a shift from JUNO pool to the OSMO pool which will continue the bonus APY till 11/1/21. OSMO price has also been down 36% in the past 30 days, it is due for increase in its price. I believe ROWAN token is also undervalued, a lot of whales were selling their early profits from the huge APY in the beginning of the bonus pools, similar to what happened with Osmosis early days. OSMO bottomed out around $1 and shot up to over $7 at one point. ROWAN should be worth much more than its current price with all the liquidity that has entered their DEX. So for me, as of today, the best pool is OSMO/ROWAN pool.
I should note that the rewards from the 350% APY on the OSMO/ROWAN pool is still less than the OSMO/DVPN pool on Osmosis of 205% APR (APY would be over 600%), however I think ROWAN token has a lot of room to increase in price, so it is a good idea to do some LP on Sifchain as well.