SQ or LO?
 

SQ has IMO lost its polish in a big way. The three versions of the long haul seats are too hard and the leg rests are inadequate - on two versions the only rise to 45 degrees which is useless. The crew are not what they used to be either. I think SQ trade on past glory.

OTOH, I see OZ as a rising star. The seats are good, the food is good and while the crew are not perfect they are willing, responsive and helpful. LO offer a very solid product which does what it claims to do, they're not five star but the seats are fine, the crews responsive and the food usually very edible.

I would choose the latter without thinking for long and you would also get to avoid a transit of FRA which is always a good thing. It's probably the worst European airport to transit.

Thank you for your advice! I flew OZ on my last flight to Asia and it was awesome. But MNL-ICN is a 4 hour flight. I think the FRA-JFK is actually the same plane, so not sure if I'd actually be connecting. Another option since i have to purchase a NRT-MNL flight anyway it to flight LX NRT-ZRH-JFK. A lot shorter layover time...how's LX in business?

Honestly, these are both really poor itineraries. How far in advance are you looking? I would probably hold out for something better.
It's a decent product. ZRH is a nice airport to transit. Excellent lounges.
I assume you are not following their current trajectory, i.e., straight down the drain. I would personally hesitate to book on OZ very far in the future. Not sure they will survive.

Also, MNL-ICN will be their regional product, which is quite uncomfortable.

I can only assume you have never transited CDG or LHR.

I'm looking for Jan 2020...so not that far out. The benefit to booking on UA vs SQ is that I might be able to change the booking (for a fee) for something more direct if it becomes available.

On SQ SIN-FRA-NYC is the same plane but you have to get off in FRA as the plane is thoroughly serviced. You are also required to be security screened and that at FRA is almost always awful. There's a thread in the LH forum about the deliberately difficult behaviour of security staff at FRA which includes refusing to speak any language except German and while I speak it I can certainly vouch for awful security experiences there over many years. An encounter with FRA security staff can make you think of the very darkest period of German history. Rumour has it that LH are starting to recruit their own staff as they have so much disruption from people missing connecting flights or just missing flights all together because they are held up in security so FRA really is a place to avoid.

LX would be a good alternative, I don't much like the seats - too coffin like for me but ZRH is a good place to connect and the lounges are passable though LX food seems on the way down at the moment. I would seriously consider LO if the price is good and connecting at WAW is easy. LO are under rated.

I've never transited LHR as it's my home airport but CDG these days compared to FRA is a pure pleasure.

I transited CDG twice in April and it was absolutely awful. I've never had a bad experience at FRA; perhaps that's just my good luck.