Bonus for SkyMiles purchase
I've observed/experienced several excellent customer service issues with Delta over the last few months. I'm now very interested in switching from United to Delta as my preferred airline. I have the DL AmEx, but use Chase Sapphire cards for most everything. Too many good benes to switch over to AmEx as our main cards. But I won't be able to transfer Chase URs over to Delta, as I could with United. Does Delta have "bonus sales" of SkyMiles once in a while? UA offers a periodic 100% bonus often enough that I could purchase miles at a beneficial rate. I use my miles for upgrades, so this could kill my switch from United to Delta. Appreciate any input or ideas.