Are integrated amps technically better than separates?

HI,
Technically yes and no. Some of the advantages are shorter paths and same vibration across the unit.
Market wants to sell seperates for profit and integrates for share. Value wise an integrated unit is hard to beat. Consider what is required as accompanying material for preamp, phono, power, transport, dac and then prey for compatibility.
Market has plenty to offer and with careful matching of amp, speakers and room size you are close.
Seperates have the more potential but demand more patience.

When I am in my more involved phase I seem to go with separates for the fun-aggravation factor. There are more variables to consider and more components, cables And cords to swap out, mix and match. Matching separates can be a double edged sword. The “ what if?” factor can easily turn into the “ why did I?”one in this wonderful hobby.

Absolutely not, High powered amplifiers need to be kept as far away from preamplifiers as possible. Ideally amplifiers should be right behind the speakers with cables as short as possible. The lower the impedance of the speaker the more important this becomes.
Integrated amps are cheap solutions for people who do not have much room or who really do not care about the absolute sound.

That is not to say that there are not some very good integrateds out there. I suppose if you had very efficient, high impedance speakers allowing you to get away with a lower powered amplifier you might be able to build a very nice system. If the integrated had preamp outs and amp ins you could add a crossover and subs improving things further. 

Just my thought, no claim to fame of being absolutely right. 
How on earth, can we accept the powersupply alone, of a power amp of say the 350 watt per channel like e.g. my X350.5 to have much in common with an e.g. 35 watt class A pre-amp powersupply requirement? 
Next, the signal level is one heck of a lot more tiny, more delicate to interference than that of the poweramp. 
Followed by, the weight of such an amp as the example is around 75kg i.e. over 150 pounds, plus about 18kg around 40 pounds for a pre-amp like e.g. my ML326S, using an alu chasis, no heavy metal. 
Adding those two up, we'd be pushing some pretty heavy integrated, just to replace the 5' IC between these two, in this example. 
To lug 150 pound is borderline acceptable for one strong person, so how about say 170—180 pounds? 
One now can argue for e.g. class D power, and not that I'd tried with some like Mola Mola monos. Didn't cut it, PASS item has simply more authority, with my 89db speakers. (2 x 8" woofers). 
So far, this clearly answers the OPs question for me in the negative. 
Oh, ok I'm invested in a nice Transparent pre to amp IC. 
Will any integrated solution sound better? 
No, as also e.g. that former ML 383 offering could not nearly do it either.
Bottom line, much depends on your speaker type of course. 
Michélle