I agree to everything quoted a above, but another advantage to the Tiribus is that you can add attachments, (longer barrel, stock, scope etc) whilst with the TiPX, you are limited to just the pistol. When it comes to pistols, i'd choose the TiPX.I currently rate the TPX over the Tiberius, but it depends on your circumstances.
If firing with 12 grams and relying on the pistol you have a theoretical disadvantage when switching CO2.
The advantage of the Tiberius with this is that each magazine has its own 12 gram, which means if you have 3 magazines you can fire and switch magazine for a quick reload. Then if convenient top up the first magazine, if not you have a 3rd ready. Keep your magazines topped up, and use the clicker on the bottom to keep track of how many times they have been used so you know when they also need the 12 gram switched.
However this means having more expensive magazines, and commiting your 12 grams by puncturing them at the start of the day.
The disadvantage of the TPX against the Tiberius for this is that because the 12 gram is in the pistol and seperate from the magazine you are committed to when you change the 12 gram.
You could slowly go through your first 2 magazines, but then get in a firefight with your 3rd and find yourself with an empty 12 gram
But TPX magazines are cheaper, and you only commit your 12 gram at the first shot. That means if carrying as a 'sidearm' then you do not necessarily have to use a single 12 gram until you first shoot. (Remembering to double tap your first shot to puncture then shoot)
However if you intend to make more use of the pistol then you should think of going to a remote line and compressed air instead of 12 grams.
The disadvantage of the Tiberius for this is you fit an adaptor to the magazine, which means you then have plenty air but have to keep reloading the magazine instead of carrying multiple magazines. (You could still carry magazines with 12 grams but there is little advantage to carrying both)
The advantage of the TPX on air is the adaptor fits to the back of the pistol (you have to leave in an empty 12 gram to maintain the seal). This means you can carry as many magazines as you want and keep loading.
But you may not like pistols with a remote line attached as it takes away some of the 'compactness' of the pistol.
Its possible to attach something like a 13ci cylinder to a Tiberius and run macro line to the adaptor, but this again bulks up the pistol and ruins the balance.
Another advantage is the TPX is a Tippmann. BZ Paintball & Tippmann tech support attend a lot of UK events so you have any techyou need ready to hand.