Well, I have used Digiwebs satellite service, and now use Fastcom; I am in Leitrim close to the norther border with Sligo.
Firstly, although Digiwebs service are OK, if you are a bit of a download freak, be warned that they do have a fair usage policy. If you go over your allowance, you have to wait for the month to roll on before they reset your speed (which they will half). Now you may think that this will occur on the anniversary of the contract or something, WRONG. This starts from the moment you go over the limit, so to get your speed back, you in effect have to stop using your connection. Plus there is no way of checking where you are in terms of your allowance, so you will be unable to ration your usage before you blow your self up. Just before I canceled my contract with them, I was down to a dial up connection speed.
Now I am with Fastcom, and I could not be happier with the service, although tech support could be quicker to answer the phone. Just tried my speed this morning, and I seem to be getting 1.87Mb down and 1.51 up, which is better than I have been getting, although they were talking of doing some work on a transmitter.
As for VOIP, I tend to use SKYPE or Yahoo, and find them both acceptable, after all I know I'm not talking down a line, and chances are I have something downloading somewhere

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My advice, Fastcom may be more expensive, I have found the whole customer experience a whole lot more pleasurable.
Hope this helps in your decision.