I started out with charge.com. Their processor was and I suppose still is ipayment. One good thing about charge.com is that they really do seem to approve everyone who can come up with the fee.
Once they approve you, though, that's the last you ever see of them. Then you are dealing with Ipayment (processor), Authorize.net (payment gateway), and whatever bank you get a merchant account from. I didn't get my merchant account through charge.com, although they offered. I already had one from my own bank and I felt uncomfortable having more than one step in the process from the same place.
Ipayment drags its feet about a lot of things and isn't always quite honest. If you squawk to them about certain fees, they say they will take them off, but they don't. When they moved a couple years ago, they suspended all payments. At first this was supposed to be for a couple days, but then it morphed into weeks. Finally I complained to the Better Business Bureau. They released the payments the next day. They claimed they were going to do that anyhow. Yeah, right.
The left hand doesn't know what the right is doing at Ipayment, either. I had to keep calling them for TWO YEARS to get them to change my address after I moved. I notified them seven times, even by certified mail. Finally they got my info updated. Meanwhile, when customers tried to call the number that was on their bill, they were getting a disconnected number. Also, Ipayment will gradually edge up your discount rate no matter how good you are. It is like dealing with a toddler who is always testing your limits. I avoid calling them for any reason, because it is just aggravating.
I tried changing to Wells Fargo as a processor/merchant account, but they told me they did not want to deal with me on account of my product, which was also the excuse my bank higher-ups used when I tried to get them as my processor. There is nothing dicey about my product, but it is vaguely similar to a product group that I know has to pay a higher discount rate. Also, I believe Wells Fargo would not have had the problem with my product if I had had higher sales. Later, other merchants told me I was better off not dealing with Wells Fargo anyway, that they were incompetent. I heard a lot of horror stories about them. But then, I have heard them about everyone.
I also tried to get a new processor from Charter One, a national bank that opened a branch here, since my own bank has no branches up here and since I don't especially like Ipayment. They had some company they had subcontracted the processing to, name started with an R, and they were actually rude to me after finding out my sales were not over $500,000/year (or even close). Yes, we would all like to eat caviar daily.
So I am stuck with Ipayment. From what I have heard from others, they are not an unusually lousy service. Customer service is simply not king in the payments processing industry.
As for Authorize.net, they were irresponsible during the last few DOS attacks on them, as far as I am concerned. For a while, they actually had a message on their voicemail that said "call back later." They had to hire a bunch of inexperienced people to deal with the onslaught of complaints, and some of them were not good at customer service. You have to pay extra for anti-fraud measures. And I also had the experience of some young pup over there laughing at me a year ago when I complained about their credit screen not working with Mozilla and I said they should fix it because "More and more people are going to be getting rid of IE." However, they are pretty good about explaining things or answering questions, IME, and I'll bet that young pup is eating his guffaws now.
As for my merchant account, my bank is best characterized as a parasite.
Hope that helps.