(1) Europa has an escape velocity that's not too far from that of our moon. Bad news; you'll need alot of fuel [most of the spacecraft's mass] to land there.

(2) The escape velocity for Enceladus is comparable to that
of a World War Two fighter aircraft. Good news; you only need
a small amount of fuel [a fraction of the spacecraft's weight] to land there.

(3) To slow a spacecraft upon arrival at Saturn so it could park in an elliptical orbit to intercept Enceladus' orbit you can use an aerobraking maneuver in Saturn's outer atmosphere. That's good news.

(4) You cannot use Jupiter's atmosphere to aerobrake into
an elliptical parking orbit [to try and intercept Europa] around that planet....That's bad news.

(5) The radiation near Europa is more severe than that around
Enceladus.

(6) The ice on Enceladus maybe a few hundred feet thick near the geysers....Good news.

(7) The ice on Europa maybe 1,000s of feet thick...Bad news.

Jake