I was going to say Sensor or Trac II, then I looked up the price. Now my answer is Dollar Shave Club twin.
The DSC Twin is the same as the Dorco Comfort Thin II (TNA3006). For this model, subscribing to DSC vs. buying in larger quantities directly from Dorco is about the same price... $36/year from DSC and around $37.50 from Dorco.
For the other models (DSC 4X = Dorco Pace 4 FRA1000, DSC Executive = Dorco Pace 6+ SXA5000) you can save substantially buying directly from Dorco. A year's worth of the DSC 4X would cost $72, while the same bought in one order from Dorco would be around $50. For the DSC Executive it comes out to $108 from DSC and around $57 from Dorco. You could even split the Dorco orders up into 6-month orders and still hit the $25 minimum for free shipping, if you don't want to buy a whole year's worth at once.
If someone really wanted to shave daily with cartridges, I'd probably point them towards Dorco's Pace Trial pack which, for $18, includes a Pace 6+ handle along with a four pack of each Pace-series blade (3, 4, 6, and 6+)... seems like a good way to try and see what exactly works for you, at least within the Pace family.
Retail pricing on Gillette-brand carts is pretty ridiculous, but they can be had for substantially less if you go through alternate channels. Try eBay or US Razor, among others. Granted, even there the pricing won't come close to rivaling Dollar Shave Club, but I personally haven't found an off-brand cart that shaves as well as Gillette, at least per my own preferences. (I confess I have not tried DSC, but at this point I'm not terribly motivated to.) I've at least managed to find Gillette carts at prices that don't make my colon clench. YMMV, of course.I was going to say Sensor or Trac II, then I looked up the price. Now my answer is Dollar Shave Club twin.