Did anyone observe the same effect?

I would say that MX-P is the best rubber for FH overall ... it is also in my opinion the best FH rubber out there (better than Tenergy05 for me).

If MX-P has a weakness, it is it's short game due to the speed of the rubber. Sure , you can keep the ball short and low BUT not in the same way as an H3 can. Placement likewise is very good for a fast rubber and on attacking fast shots its super precise, but on very short tight situations there will be rubbers (like H3) which give more precision. 

Apart from that MX-P has excellent serves, excellent spin, spin increases as you put more power - there is no real upper limit, it's good from all distances (close because the throw is not as high as Tenergy) and far because it has immense power / counterlooping abilities, catapult.

Passive blocking is great because the rubber is fast and every block is a threat, it is not as sensitive to spin as Tenergy05, but maybe Victas is even less sensitive.

It's absolutely consistent. It is not an all round rubber, it rewards attacking more than anything, however it does everything well. 

I especially like that with the MX-P you can spin the ball in many ways, hitting through the sponge, brushing, slow spinny loops, powerloops, even flat hits, or side spin FH attacks are great.

On the attack the only area i don't like so much is the smash -  love smashing a high ball and it is one of my best shots, but with the MX-P it's important to add just a tiny but of spin, not play for the pure flat smash, otherwise the control reduces a lot and it can go long or even fall into the net at times. It is easy to add that tiny bit of spin to solve the issue but I don't feel it as satisfying as a pure smash like at the time of my old favourite the Stiga Mendo MP (90s!). 

To me, V15 extra is one of the best rubbers for playing defensive strokes and being able to make the offensive transition. MXP is very hard to deal with if you want to chop from behind.

The OP didn’t say anything about chopping from behind!

Hey, would you recommend v15 extra for modern defence? How does it compare to chinese rubbers? Cuz I'm trying to find an alternative to my hurricane due to its weight, but most European rubbers are either too fast for chopping or too slow for powerlooping.

P.s. I have had it on my forehand since late 2018 so you can say I know it fairly well  

Then, how do you like it as a BH rubber? Do you find it suitable for both BH and FH, for an all round, but aggressive game? 

I did play with TG3 and Hurricane in defense but the weight is very heavy and the problem is also that you need to bbost the hurricane otherwise, it is not possible to counterattack. It increases the weight and it becomes less convenient for a regular chopping game: sometimes you chop 1 ball very good and then, the next one, you send it in the low part of the net. V15 extra is very good for chopping, fishing and counterattacking...and I don't boost it.

V15 is an excellent bh rubber. My son plays a softer version, limber, on both sides. I have v15 extra on both sides of my training/multiball blade and it's a very good all-around rubber.

i tried boosting worn v15s in the past ... When I say  worn, its topsheet is still very grippy but the sponge is dead (2-3 months of use).

In my experience booster extends its life by maybe 3-4 hours and that's it. Totally useless for me.

New V15 out of the packaging plays very very good without any booster.

I just boost it to break it in, it's too hard for the backhand for me without it

Then for the next few months it plays great!

That is interesting to me, because MXP does everything i want from it from an attacking sense, so i largely agree with you. Slow loops, fast loops and pure flat hits. The ability for the rubber to support having 3 attacks that are completely different [in speed and spin, therefore requiring more adjustment and skill from an opponent to contend with] is very useful.  

I play with the MXP on the forehand and utilize flat smashes extensively and I've never had a problem attaining consistency aside from when its an issue with me [i.e. didn't play for a few weeks  so a bit off in some sense etc]. The easiest balls to hit straight through are light topspin / nospin, and the higher above the net the easier too as more margin for error.

The most important indicator to me for making flat FH or BH smashes is correct foot placement. If you are able to position well and have the technique / timing down, there is no reason you shouldn't make 90+% on FH or BH flat smashes when someone is lobbing / allowing me to smash in either training or a training match. In a competitive match, the goal is to get as close to that training # as possible, given the additional pressure causes one thing or the other to break down - but if you can get a high % in training, that means its not the rubbers fault, no?

If you were using and actively remembering rubber that is 30 years old (90s), I'm guessing the feet aren't quite as quick as they used to be, and that's what might make smaller things like the rubber not being absolutely 100% suited, a bigger deal.

The main weaknesses if nitpicking with MX-P to me, is the weight and longevity. The latter is counteracted by how cheap it is (110 odd euro gets you 4 sheets shipped at any time from multiple sellers), so the main one is the weight. An MXP plus an ESN BH rubber on most blades leaves you in the 190s for overall bat weight