Other than the RF band that the TSU7500 uses, I can't think of anything. The RU990 works within a higher RF band width. If you wanted the future use of an RF extender, you would need to buy the North American model.

I can't comment yes or no, but I strongly suggest that you do a little research into the IR operating frequencies of European equipment in comparison to the TSU7500 IR output (and RFX6500) to see if they will communicate easily. Philips details that the TSU7500 will learn codes higher than the normal operating range, but you never know.

Now the power adapter I can say will not work for you. I'm not 100% but do believe that the European receptacles (wall outlets) aren't even physically the same as the North American type. So you shouldn't be able to plug in the base. If you could, you would fry the adapter. With luck before it managed to destroy your remote.

Again, I'm not certain but I think European power is has a frequency of 50Hz....? (North America is 60Hz) That may also create problems. The battery would charge, not as well, but it would. However if the Pronto draws direct power when in the cradle rather than from the battery, it may adversely affect the remote. That's getting into some hard core ripple voltage math from the power adapter but it is a possibility. A European adapter needs to be more tightly regulated to produce DC the same as a North American model. That would come down to how sensitive the electronics are, and I don't know.

You would need to buy an adapter that is available to convert the European style pin configuration to the North American format. I'm not sure whether they also step down the voltage or not. The North American Pronto doesn't switch.

I'd look a little harder for European pricing. I just did a quick search and the RU990 after conversion was a couple of hundred more. After accessories you would need and shipping they really wouldn't be too far apart.

I would suggest if the Pronto is the way you want to go, buy the RU990. Sure you will take a small hit in price but when you weigh in the lack of warranty. (There is no way Philips would warranty a piece being used on a different power system then it was designed for.) The extra cost is worth not having to deal with potential headaches. That is, even if it works perfectly with European equipment.

Best of luck...!