I presume we are talking about RotS Master Kenobi here?
If so, Obi-wan clearly has all advantages when it comes to lightsaber ability.
Force prowess however is quite the opposite story, Obi-Wan certainly had a powerful Push, but he was not a master of force ability, this area however, is where Surik shines.
She was probably the most powerful light sider of her time.
By the end of KotOR II, she was an enlightened Jedi, this ability is very rare amongst Light siders, it basically gives them a much deeper understanding of the force over all, she knew the light unlike anyone of her time.
She was the reverse of Nihilus in that she would create connections that would enhance the other user, instead of drain them, it is how she made her Padawans so powerful so quickly, as well as this, she learnt a moving meditation, ways to shield her thoughts, and better yet, she could use Dun Moch to defeat even the most stubborn opponents in a battle of wits.
She was the single reason the galaxy survived, she stopped the Sith, stabilized the Republic and stopped it's collapse, she rebuilt the entire Jedi Order and brought back what it truly meant to be a Jedi, even when the Jedi Council had turned away from that, she helped Revan, saved Revan, is the only reason he survives still.
When taking a look at her lightsaber ability, we only need to look at her duel with Sion, he was immortal, he had no reason to defend himself, he had over a hundred years of experience in killing Jedi, yet after a long duel, he could not land the killing blow on Surik, even for such a time to let her convince him to die and reject the Dark Side sustaining him.
She was the only force user to face Darth Nihilus and not be instantly fed off of and killed, due to her being a wound in the force.
I haven't seen Obi-Wan demonstrate the same type of command of the force as Surik had, but he was clearly the better Lightsaber duellist by a long long way, this all depends on how they engage and who has the best control in a duel, if Surik can keep Obi-Wan at bayt long enough, her command of the force could defeat him, but if it comes down to a duel, Master Kenobi wins hands down.