I have been doing some research as well, and settled on the Chase United MileagePlus card.
I'm in a similar situation in that I travel less than 5 times/year. Here is what enticed me:
- Availability of United flights from local airport
- Free access to airport lounge (2 passes/year)
- VIP lounges that pop up at malls at year-end
- 50,000 point sign-up bonus
Hope this helps.
Macy's Red Star - $5100 (1/2010)
AMEX Everyday - $9000 (1/2011 Backdated)
AMEX Green Corporate - NPSL
Chase Amazon Prime - $8900 (11/2011)
Lowe's/SYNCB - $6500 (7/2014)
J. Crew/CB - $3500 (2/2015)
Target REDcard - $500 (11/2015)
Citi AAdvantage - $4000 (6/2016)
Chase United MileagePlus - $5000 (2/2017)