Motorcycle Questions? Ask a Mechanic.
The biggest difference between these two will be the fact of your bike having carb fuel delivery, versus fuel injection. There are some benefits to both. The phantom with its fuel injection will allow you to simply turn the key on, then go ride. Alot of times with the carb bike like your year of VTX you will need to allow the bike to warm up a minute or two before getting the bike to run well without the choke on. When it comes to storage periods the fuel injection wins. Carb bikes when the sit for a while unused will give the threat of jetting being clogged. Fuel injection this is not an issue. However when performing upgrades such as an aftermarket exhaust or intake. A fuel controller would need to be purchased to adjust fuel parameters on the fuel injected phantom. The carb bike would be a change in carb jetting. So fuel delivery is a bit different on both. However as far as the rest of the bike goes. The VTX is a much better handling bike for more open road, higher speed, longer travel. More power and stability versus the phantom. The phantom is a great handling bike. But when it comes to interstate travel, the VTX is the better choice. Also the VTX is better handling with passengers. In my opinion it would be a slight downgrade to switch to the phantom. You will be at a lose of power, and size of bike. Both bikes are well built and should withstand a long lifetime of use.
Any further questions let me know, thanks