I would not recommend Electro Alarma.
Actually, I have experience with both Alerta & Electro Alarma. I used Alerta about 6 years ago to install an alarm system in my house. They did a professional, albiet expensive job. It has worked flawlessly since installation. Less than a year ago, I had Junior at Electro Alarma install a closed circuit tv monitoring system at my business. First, he tried to pass off a used vcr recorder as a new one, when we caught this obvious trick, he reluctantly exchanged it. Next, the coaxial connections he made were simply spliced and taped together, not using the coxial connectors necessary for a good connection and a good quality picture. He promised he would change to the connectors as soon as he got them in. It has been almost a year now with us calling almost every week and he will not return to complete his work. We have had two cameras essentially out of service for this period of time and have repeatly called him to resolve this problem. He always promises that he will be over "later this week" to resolve it but obviously has no intention of standing behind his work. Based upon my experience, I would not recommend Electro Alarma or Junior (the owner).