fixed or variable spreads?

Are there any brokers that offer fixed spreads and don't requote, disconnect or any other shady stuff? Or can you expect stuff like that from every broker with a trading desk? Even if they guarantee that it won't happen?
Conversly, are brokers with a variable spread more trustworthy by default?

I'm especially concerned about disconnects and avoiding large slippage, since I intend to do automated trading.

If you trade, you are going to experience this no matter what. If you live in a climate that has rough winters like I do in the northeastern USA, you might experience a power outage, phone service disruption, or being snowed in.

In any case, your decision should not be based on the problems. There is no guarantee in trading or in life. If a broker gives you a guarantee, look for the "Acts of God" clause.

If you seek a guarantee, it may be safer for you to keep your money in a bank certificate of deposit.

Ok. Let me clarify. I'm not looking for 100% sure thing. Obviously nothing in life is 100%
What I AM looking for is the best/most reputable broker for automated trading, and if this entails fixed or variable spreads. (Since I have backtested with fixed spreads, obviously I would prefer that.)
Anyone succesful in his/hers automated trading pursuits that would care to give some input?

As far as power outages and the sort, I plan on having my setup on a dedicated server to minimize the risks for disconnects on my side.

Hey quathar,<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o></o>

The people involve in forex trading have to know that this kind of things are part of the rules of the game. Everybody is in it for the quick buck, and every broker will slip you a couple of pips (you should only worry of those who’s slip you several tens of pips and requote you all the time). I know that, and I take it into account for my trading.<o></o>

Variable/fixed spreads is a quite interesting question, I personally don’t see any advantage of the variable spreads, but I think you should have the opinion of someone trading with variable spreads. That would definitely be a interesting point of view.<o></o>

I.

You do realize that just because a broker has variable spreads doesn't mean you have to pay the spread. Most ECNs will allow you to place trades within the spread (effectively allowing you to "make" the spread), so if you're worried about getting in at a bad price simply place a limit order within the spread and you'll be good to go. If your liquidity provider is working with many reputable banks, your order will probably be filled and you'll experience no slippage.

The issue of slippage only deals when you're trying to get into a really fast market in which case trying to put in a limit order would, well, limit you. However slippage in this case is absolutely unavoidable, right? You can't expect to catch a price that's moving impossibly fast to catch AND get the best price.

I think more than anything you're really going to have to learn to live with the slip. Just tweak your system to expect a certain amount of slippage. If you're actually good at what you do, your system will be profitable despite the slippage.