Your sub experience: Easy or hard?

Since I use a sub for "bass fill" to obtain full range sound in a good room, not difficult. I suppose if one is a home theater fan and going for dramatic effects it would be much more difficult. I have a two channel system, so I can pretty much set it and forget it. 

I tried subwoofers with Magnepan 0.7's with no luck. I wired them up with a pair of DW-M bass panels which filled in the lower frequencies with much better integration. I connected the 0.7's to the 4 Ohm outputs on may Hammond 1642 SE Transformers and the two 4 Ohm elements in each DW-M in series and in phase with the 8 to 16 Ohm transformer outputs. 

In my weight training room I built a 45 SET which uses Goldwood GT 1118 pizo tweeters mounted in Parts Express 294-2924 horns and DS1B PRO-X6BM speakers with first order crossover 0.3 mH chokes. This kind of speaker system does well with a subwoofer. 

I think it depends. I got a sub because my room has poor bass response. Lots of experimenting, and lots of long listening sessions. My goal was to have it integrate with my main speakers and call no attention to itself. If Vandersteen Quatros were on a half price sale I would’ve gone that route. I have Vandersteen 2Ce sig. II’s. I added a V. SUB3, and a M5-HPB crossover. Once I embraced that a lot of the setup is personal preference, it was just a matter of extended listening, and fiddling with the settings. I’m happy with it. But, it may be a while before I want to listen to anymore solo upright bass recordings.

“Subs are a pain in the pitootie.”

100%

I agree with comments that variation in recordings makes subs tricky even when you get it set up right for the room. I have a REL T2, which they call sub-bass. I'm a bass player, so I always notice thin bass and enjoy this sub's addition. But I am jumping up to adjust the volume of the sub between contemporary pop/rock recordings and most before 2000. Jazz is more consistent, but contemporary jazz is also produced with more low bass. This makes the sub a little more like a tone control than I'd prefer, but there's no way around it in my system and my listening. I should caveat that I've not had the opportunity (i.e., budget) for a truly full range tower in my system so these comments are about stand mounts and my current Magnepan LRS.