Railbookers

Many of us here, who have traveled a great deal, suggest you stick with booking direct rather than using a third party.

If all that's available are the aisle seats, go for them. Both of these trains have larger than normal windows so you won't miss much from either side. of the train.

Don't use third party vendors- too much can go wrong.
You can ride the regional trains that run on the exact same tracks and don't require seat reservations. It's the trains the locals use. We rode the regionals and loved it! These trains aren't crowded, the windows open, which is great for taking pix, and you usually can jump across the aisles as the scenery changes.
Enjoy this beautiful country!

Please do some searches for reviews on Railbookers, which is a travel agency. There are quite a few threads across Trip Advisor with stories of terrible service with this company. I do not have personal experience with them.

Why use a third party at all? And as was said, the "normal" priced trains run on the same tracks and see the same things.

We took this trip in May, 2025. Get a travel agent if you want to have someone plan you travel by train in Europe. We started in Naples to Sorrento, then Sicily. The only thing they did right was picking Taormina, Sicily and even that was a fiasco. First, they didn't include transports to and from all of our locations and when I asked why, they said it would be less expensive to catch a taxi than to book a transport service, which is fine, but why did I need to ask? Next they gave us vouchers for the train rides without any explanation that we had to turn them in for tickets or that we would need to transfer trains in Sicily to get to Taormina. We ended up on the west side of the island before we realized that we needed to transfer to get the east (Taormina) side. When we got off we discovered it would take 4-5 hours to get back to Taormina by train due to the schedule. We paid 150 euro for a taxi so we could get to our destination in a little over an hour and Railbookers refused to pay for that mistake. Finally, we decided not to go on the excursion to Mt Etna because I was feeling motion sick from all of the other transports we had been taking and the voucher from the excursion company said we could cancel for a refund within 24 hours and we canceled with over a 48 hour notice. Railbookers refused to issue the refund that they got back from the excursion. What an awful company!

We did the Glacier Express last August. We were a party of six and four of us had aisle seats. The windows are huge and I don’t remember any complaints about not being able to see.