After months of dreaming about IMBC, I finally got the courage to make it. I've never tasted it before, so had no expectations except all the rave reviews I've read from other people.

It tasted like creamed butter with a bit of sugar in it... I didn't like it....

Is this a common reaction, or did I do something wrong? What's it SUPPOSED to taste like?

You've got it!! You either love it or you hate it is the common reactions that I hear. Also, did you use any type of flavoring? Vanilla or almond, etc?? I find that adding my flavor combo minus the butter flavoring (a combo of vanilla, almond, butter, orange and lemon extracts) usually makes the difference. Or, there a some people that add things like coffee, or melted chocolate, etc and that's good too. But, back to your original question...yes, it is very buttery.

I tasted it (bleh), added some vanilla in (still bleh), then added some passionfruit curd in (slightly less bleh, but still too buttery).

So chances are I just don't like it? My friend tells me that unless I didn't put enough sugar in by accident, maybe it's just that I don't like IMBC. I also used salted butter, because unsalted is more expensive, and I have never found it makes a difference with other things. But maybe it does with this recipe....?

I wondered if the butter here in NZ is just wildly different, so is overpowering. Our dairy products are very different to those I used while living in the U.S., so possibly is a reason? The buttery taste was what really bothers me, not so much the sweetness.

Yes, IMBC IS very buttery. However, I am (unfortunately!!) not familiar with the dairy products that you have in your country, it very well could be that. But, someone that has tasted both could only answer that one for you.
I can tell you that when I whipped mine, I added in some powdered sugar to it just to stiffen it up a little bit. And, you can also try adding 2 tsp vanilla, 2 tsp almond extract, 3/4 tsp orange extract and 1/4 tsp lemon extract and see if those things help the taste any.

Im from South Africa and also had the same reaction, its like a mouth full of buttered sugar

I also put it down to the difference in products.

I guess it could be...but then, how different are the dairy products on Australia and Africa?? Are they totally different in taste than all of the other continents? I mean if you think about it IMBC, SMBC, and FMBC (French, which is actually more of a custard and my personal favorite of all three) were all developed in countries other than America, so it could just boil down to a preference and not to a product difference. I mean, I do know that the butter fat content is much higher in Europe than it is here. But to me that would just make it taste better. (again, preference)...

I thought the same thing the first time I tried it. Then I learned that in this case, unsalted butter DOES matter. I also found a recipe that uses more sugar and flavoring than the first one, and now I love it. (I actually switched to SMBC, because I think it's easier, but the idea is the same.)

Here's the recipe I use: http://cakecentral.com/recipes/5453/the-well-dressed-cake-swiss-meringue-buttercream-with-variations

I make SMBC exclusively and I never use salted butter. I read in some other threads that with the MBCs you should always use unsalted because the salted butter will cause more of the sweet butter taste.

The icing is buttery but from my experience with SMBC (very similar to IMBC) is that it tastes like rich ice cream. It can also handle a lot of flavor, too. Well, that's the response I get from people that aren't cakers.

But like everyone else says, its all about your preference. Maybe try a half batch using unsalted butter to see if it makes a difference?

Well, I made it again, this time with unsalted butter. I do believe it made quite a big difference, you're right saffronica, it does matter in this case.

However it still does seem a bit like overly creamed butter, so I would be keen to give that recipe a go, thanks. It looks the same except for less butter, which seems like a good idea!

I kept tasting it, and in the end decided that I do like it. It's delicate, an interesting texture. Once I stop thinking about the butter, I can appreciate it for what it is. In my mind, it's not better or worse than plain old buttercream, it's just different.

I just recently tried this icing as well, and I had the same reaction - this tastes like creamed butter. I'm pretty sure I used unsalted butter, and I'm from Canada, so I don't expect the products to be too different. One thing I didn't like about it that I love about buttercream is it didn't freeze well at all - well, it froze well, it just didn't unthaw well...and remixing it didn't do anything but make it into a runny mess. Anyways, needless to say I've stuck to buttercream, but maybe I should try the SMBC - I just hate throwing away stuff that doesn't work out.

Don't toss it!! My "signature" icing is made from a combo of SMBC and regular buttercream (conf. sugar based). Everyone that trys it absolutely loves it. It's a dream to work with, doesn't crust and seems to appeal to everyone (kids & grownups!)

So try something new -- make a batch of your regular buttercream and blend in with the SMBC (preferable the unsalted batch or you could blend those two together with a double batch of regular buttercream).

I make SMBC and it is my absolute favorite and if I had my way I'd never make another kind of frosting! I read on here in various other threads that definitely do not use salted butter because it will give the icing a strong butter flavor. Also, I find that I use much more flavoring than shortening/powdered sugar buttercream.

I did use an organic "cultured" butter once and it had a much stronger butter flavor and made the SMBC much stiffer, not so light and fluffy. So perhaps you can experiment with different butters available to you to see what works best.

I'm glad it worked better for you the second time around. And you're right, the texture is very different from powdered sugar-based buttercreams. That silky texture is what I like most about it.

I also freeze my SMBC. Since I make a lot of recipes that use egg yolks, I freeze the extra whites until I have enough for a big batch of icing, then I make the SMBC whether I need it or not. I make it either plain or vanilla, then freeze it. Then I add the flavorings (extracts, melted and cooled chocolate, fruit purees, peanut butter, etc.) when I rewhip it. I freeze the icing until I need it, which means less prep work when I actually do a cake. Today, for example, I'm doing a double-layer half sheet for my daughter's school. It took a lot of icing, and I was especially glad I didn't have to spend time making it on Wednesday when my other daughter ended up sick.