Host Your Autoresponder or not

I have tried several autoresponders and I really liked Aweber, but then after a while I thought why pay $19.95 a month when you can buy an autoresponder install it on your site and then don't have to pay for it ever again? For the past year or so I have been hosting my own autoresponder and it has been working great, I have had no problems at all. But when I think of it, I am not sure if it was a smart move or not. The reason to host the autoresponder yourself is first and foremost a question of economy. If you have your own hosting account, then it won't (probably) cost you anything extra to install it on your site. And you have full control of the autoresponder when it comes to adding leads and whatever you are up to. But as I see it, when it comes to spamming, I will probably have a bigger problem with my own autoresponder than if I used Aweber. I don't know this, but I would think that it would be easier to prove that I didn't spam if I used Aweber. They probably track close to everything and I wouldn't get the address in the optin list if I cheated (or maybe I could, not sure about that). A problem with hosting the autoresponder yourself is that you can't export your leads into Aweber (or most of the professional autoresponders), this is because they want to prevent "cheating". I am not sure if I remember this correctly, but I think that every lead in your autoresponder at Aweber has to be collected using Aweber. I think that this is a good thing, even though it complicates things if you want to switch to another autoresponder. Then you might be "losing" a lot of leads. Another problem is that when you host your own autoresponder (and you don't have a dedicated server), there will probably be some sort of limit to how many leads you can have in your list and send to on a regular basis. I am not sure how big your list can be and it probably varies from host to host, but it would be very interesting to know this. I am hosting my own autoresonder, but I don't know for how long.