Mind that since 2006 I've been listening to music through studio monitors and not hifi speakers and that my old 5" Tascam monitors had gone south, I wanted to keep the budget as low as possible as although I could afford speakers with three times the price, I am not a pro and nowadays I am very practical; just buy something that would do the job and be done with it instead of chasing your own tail.
I read a lot, I listened to some comparisons and I pulled the trigger and bought those and paired them with my Behringer UMC404HD (yet another excellent product that beats products with double the price, but that's another story).
I get anything from zero to some hiss but that depends on the room I use them and the outlet configuration so I know it's not the speakers that may or will cause any hiss (always TRS connection and volume set on max). So, that's that.
I use them in untreated 12-20 square meter rooms, volume wise there is no way you will ever need more volume than they can provide even if you want to throw a small party in the house (50 square meters).
In terms of acoustic treatment, there are at least 3 different settings you can adjust to make things sound right (either by ear or by taking measurements and go from there) but to be honest I only set the bass freqs to -2db as no matter the room, I place them relatively close to the walls (less than 20cm, that is) so that's what gives me the most balanced sound in terms of bass frequencies, but ymmv.
Now, the most important part, the frequencies themselves. There are dozens if not hundreads of monitor speakers out there that are supposed to be flat but they are all different. The trick here is to pick the ones that fits your work in terms of sound fidelity, if you can, and if you own more than one set of monitors so you can cross-reference (different brands/models) that's great too. I find the E5's very balanced, not mid heavy than some of the star monitors out there, not high heavy and not bass heavy either (always by my standards, again, ymmv).
OK, now for the the bass freqs comment since most people out there may think that 5" monitors can't cope with those. Let me put it this way, If you love super accentuated bass freqs, and I am talking about freqs that don't even exist on an original recording (no matter if it's your creation or someone else's) then for your own good just forget all about studio/reference monitors and just buy big HiFi speakers, you will be more happy with that choice. If you are instrested in listening excactly or close enough of what has been recorded and your room is not humongous and you are after a nearfield pair of monitors, then the 5" ones will do just fine and in some cases way better than most of the bigger ones. And if your music consists of sub-bass freqs just look for something else (studio moniors + subwoofer, bigger studio monitors etc.).
The music I record comes from electric guitars and all of them are tuned in standard D, electric bass with 55-110 strings tuned in standard D etc. I can hear everything on the E5's and pretty much as they were recorded. In fact as I am writting this review, I am listening to some Miles Davis mid fifties music and I can hear the uptight bass loud and clear (and that's with -2db on the bass freqs due to speaker placement).
Now, a funny, story, a week after I bough these I invited a dear friend of mine which not only happens to be a professional musician but he also has a recording studio and does recordings/mixing/productions for a living. He owns several studio monitors and not the ones you will find for less than 1000 bucks. So, I told him to check the sound balance because I was a bitt worried about the placement etc. He played through them a few of his songs that he had mixed with his superpro gear just a few weeks before. Within the first seconds he found a few flaws of his mixing that had to do with the drum case! Then we played quite a few of studio recordings of other artists and he just gave me a thumbs up while he was scratching his head about the price. Funny, isn't it?
All in all, sorry but no, the E5's are not the "bestest" of all, there is no such thing. They are VERY balanced and sure a pair of HS5's (more mid and high heavy in my opinion) or 305's (somewhere between the E5's and HS5's in my opinion) may suit you more but those have the best balance for what I do.
I'll be ordering another pair of these for my living room which is where I record (not mix) my music, listen to music, watching movied etc. as I moved them and tried them just to see what they could do and I just love them! That way I would be able to set the guitars and bass sound before the actual recording to properly fit in future mixes (instead of recording first with a particular sound and then EQ it to death to make it sit and cut in a mix).
In conclusion, If you'll be working in relatively small rooms, you don't want to break the bank and your main focus is on mixing/tracking/production (as long as you don't care about sub-bass frequencies) then those should be one of the first candindates.