I have experience with the Ikon and the Sunbeam EM4800, which is a pretty similar machine to the Cafe Roma.
As youre probably aware, the major difference between them is that the CR is a thermoblock machine whilst the Ikon is a boiler. You may be able to temperature surf to some extent on the Ikon to try and optimise results.
My guess is that you wont see a huge improvement by upgrading to the Ikon. Ive been into my espresso for around 3 months now and feel I still have considerable improvements to make in my tamping, dosing and grinder setting knowledge. It does not help that I have lots of different pieces of equipment to play with.
Once you feel youve mastered these, you can then start playing around with different blends of beans or even start roasting yourself with a popcorn machine.