I would recommend against integrating your account into steam. It's not that bad, but I have found that it's only made it worse, albiet only very slightly. I've yet to use the voice chat at all and anyone who tells you that you are bad because you do not is full of [scrap].

In-game voice chats worse than Skype worse than Ventrilo/Mumble/Teamspeak

If they are at all serious they would use skype or some other VOIP program

Some of the minor inconveniences that I have experienced:
The Steam overlay doesn't work unless I change the key that calls it (haven't tried)
My files are now even more obscure and hidden (spiral spy)
Problems with steam so now instead of wondering if the server down or if it's my internet, I now have to ALSO factor in that it might be steam
steam is the devil
Another program that must be running to run Spiral knights
Buying things through steam is ok, except when you want to buy an expansion. Then it gets [frakking] weird. (like the armor pack)

My computer is very fast and so is my internet connection, but I can only imagine that another open program during play will make it slower.

@Bohhty:
The overlay works fine, and Steam takes up no internet usage to have open, so makes zero difference to your game connection unless you're downloading on Steam or playing another online game

@OP:
Seriously, there's countless threads asking about this, just search it up and get dozens of responses arguing both sides of the discussion.

It mine as well be the same as the built in voice chats. Especially steams.

@Darkbrady
Not internet usage *facepalm* memory usage, which it does. xD

You don't need voice communication to do anything in spiral knights successfully. I can attest to this.

There is no good reason to switch to steam.

It depends on the system. I run Spiral Knights on a macbook air and it doesn't cause lag, but it over heats and closing things I'm not using helps it not over heat.

Right, which is why OP should not convert to steam.

If you have a computer that's any good (over 2GB RAM), then running Steam in the background will most likely NOT introduce any lag, and the overlay maybe only eats up one frame per second at the MOST. If you want to disable it, then do so. There is some steam-exclusive content and you can trade SK stuff via Steam trade, which can be good if you find good deals. I haven't found a problem with having a Steam account, and most downtime is a wrench in Steam's server, as was said earlier.

Most people who tout steam really blow the downsides out of proportion. If you have a capable computer and internet connection, then you'll not notice any difference.

I think the real question is whether or not you are interested in using Steam for any games besides sk. It probably isn't worth it to make an account just for one game, especially when it can cause minor complications to the log in and updating processes (as we're seeing now). However, I think that Steam is a great service for any gamer. I like having my games all in one place, having a unified friends list, and having all my playing times/stats easy to view. They also have great sales. I probably own 50+ games that I've either gotten for free or paid less than a dollar for. And I haven't had any problems with the voice chat through Steam. I think that the inconsistent quality has less to do with the service and more to do with people trying to use the mics that are built into their computers instead of getting decent headsets. It also really annoys me to have to go outside of the game to run chat services like skype, especially to chat with people who aren't my friends irl.