Freesat may have more channels, but from an installation point-of-view it's a PITA. However, that can be fixed.
Here's the basic issue: With Freeview, you can take one aerial cable in to a room and loop it through a Freeview recorder with up to 4 internal tuners, and then go on to connect a TV. With Freesat, you can't do that. Every tuner requires its own feed from the dish. With Freesat then, a room with a Freesat TV (1 tuner) and a Freesat recorder (2 tuners) requires 3 cables if you wish for everything to work. Why might you want a recorder in the room? Well, does your TV offer the pause-live-TV feature?
The reason why Freeview can supply multiple tuners from a single cable is that the tuners are passive. The signal cable carries all channels available at the location, and all the tuner has to do is tap in to that. Freesat and Sky satellite is different.
The satellite tuner and the LNB (the lump on the end of the satellite dish arm where the cables connect) work together; the tuner is active and it directs the LNB to switch between one of four states depending on the channel being received. It does this by sending a voltage up the cable to the LNB to change the polarisation between horizontal and vertical, and by altering a voltage state between 15v and 19v (allowing for voltage drop over cable).
Technically, it's possible to split a single satellite LNB feed between two tuners - say two TVs - and watch two different programmes, but only if those two channels share the same polarisation and voltage. As soon as one TV calls for a channel that requires a different combination of H/V and voltage then one or other TV will lose its signal. This is why, in reality, you can't split satellite signal cables.
When it comes to installing, the same type of dish and LNB that works for Sky also works for Freesat. This is because the signals come from the same satellite. The LNBs for Sky+HD (not Sky Q!) have four outputs. They're called Quad LNBs. It's also possible to get an 8-output version referred to as an Octo. If you need more than 8 then it's often a second dish. At this point you're probably totting up how many TVs and possibly the recorders you might want to have now and in the future, then thinking that the house is going to be festooned in bits of black wire. That's why I said that Freesat is a PITA to install.
Here's how to fix that.
Instead of going for a conventional Quad LNB, it's possible to use something called Quattro LNB with a multiswitch.
The Quattro outputs all four signal states at the same time; one output for each version. These signals go to the multiswitch. This device acts like a matrix switch for Freesat and Freeview signals. It reads the call from the tuners connected on each of its outputs and then supplies the correct signal. There are various sizes of multiswitch available based on the number of outputs; 8-way, 12-, 16-, 24-, and 32-way are common.
I mentioned that the multiswitch will also handle Freeview. Personally, I would install an aerial as a matter of course even if your main viewing will be done with Freesat. Unless you're in an area with diabolical Freeview reception, then having the backup of Freeview makes sense. Every modern TV has a Freeview or Freeview HD tuner. Also, in heavy downpours I have lost satellite reception as the dish mesh has saturated with water. I have never lost Freeview reception at those times. Have a V36 Log Periodic aerial put up and feed its signal in to the MS.