I'm just now getting into aggressively going after points/miles, so I think it's time to re-evaluate where I stand.

I currently have a Chase UMP Visa. Wife & I just signed up for the Amex Platinum with the 100k bonus (thanks FT!) So that puts us at 200k MR points, plus about 100k UMP miles I have currently.

I am thinking about getting either the United Explorer or the Chase Sapphire card. Is there a reason to prefer one to the other? I am leaning toward Sapphire but not wedded to it.

I often fly UA/CO -- EWR is the most convenient airport to me -- but I can pretty easily get to LGA and JFK so I'm not wedded to sticking with UA/CO. I'm considering hitting my spend on the Amexes, then getting the Sapphire as an everyday card and putting the current UMP Visa on ice (figuratively). But if this is a bad idea for some reason, would love any advice.

I'm not strongly opposed to an AA card, though they just seem not to be the best airline for me most times. I'd have no problem going with DL, though the best deal I've seen is 50k miles, which is why I figure, why not just go with the Sapphire...

Isn't CO leaving the Chase Sapphire family shortly? That would leave you without a way to consolidate your miles into UA/CO program. Your only airline transfer options at the moment are BA and CO with this card which makes it less palatable to me.

For the UA Explorer card make sure you will hit the spend thresholds to maximize the bonuses. IMHO their current bonus offer is poor. I would wait a while to see if they make it better. You have to spend $25k on the card in the first year plus add authorized users just to get 40k bonus miles.

I got in on the 2 AA cards with 75k bonuses a while back. Of course those miles are good for booking anyone in OW, not just AA. So I think it's worthwhile to collect miles in both of the big alliances at least.

You may want to consider a card like the SPG Amex that a lot of us like. Not a huge sign up bonus at the moment. But you can use SPG points on a lot of airlines. Unfortunately their UA transfer ratio is poor. Or you could go for an Amex rewards gold or plat card.

Of course it also depends on what you are trying to get out of this. Do you want as many miles as possible to fly international premium cabins? Or are looking to fly domestic Y?

No one at this point knows whether UA will take CO's place in the Sapphire Preferred list of airline partners, but with Chase's close relationship with UA, it's not a bad bet. Until CO goes away in the merger, you can take the bonus points from Chase, transfer them to CO, and then merge them into the Mileage Plus plan. Given the 7% annual bonus on all points earned during the year, effectively making the signup bonus 53,500, and the 2 points/dollar spent on travel and restaurants, the Sapphire Preferred looks like an increasingly good option.

I'm an AA person myself, but that's because AA is a good option out of my airport. I think you've approached this the right way by trying to figure out a plan that meets your travel needs. AA and BA, the Sapphire Preferred's other airline partner, both fly out of JFK. For international travel on BA, you'll have to contend with high fuel surcharges, but I've found good value in using BA miles for international travel in higher classes. Plus, you can book BA flights using AA miles and AA flights with BA miles.

The Chase/Southwest card might also be appealing now since Southwest flies out of LGA and apparently wants to increase their presence at EWR. 50,000 RR points, only a first purchase requirement to earn the miles, and a 6000-point annual bonus that roughly equals the cost of the annual renewal fee make for a pretty good option. With the tight correlation between the cost of flights and the use of RR points, this card offers plenty of opportunities for reducing flight cost on shorter routes. I think it's a nice supplement to the Sapphire Preferred.