According to the Epson homepage, the model ECOTANK ET-4700 UNLIMITED is technically identical to the Eco Tank ET-4700.
The only difference with the UNLIMITED model is that the "unlimited printing" service is included: you get 2 years of free refill ink for this EcoTank printer.
For Fr. 300.-- extra, you can buy a minimum of 22 refill ink bottles at Digitec, which should be enough for about 22,000 pages of printing - if all 4 colours are used evenly. In the meantime, however, there may also be imitation refill ink or original ink with a quantity discount could also be cheaper than in my example calculation. Conclusion: whether the Unlimited model is worthwhile depends on the individual print output per year.

unfortunately no idea...