Any modern band that comes close to Mahavishnu Orchestra ?

Tony Williams Lifetime
Alan Holdsworth
The Fents
Return To Forever
Early George Duke
Wishful Thinking

I think The Mahavishnu Orchestra had/has no rivals.  The instrumentation alone makes them completely unique.  The band had a power, an energy and an impact that can't be duplicated.   However, there are fusion elements in the band's works that most fusion bands have.  If you like the soaring energy and the blazing musical speed you might like some of the later King Crimson music (THRAK, THRaKaTTaK, ProjecKts).

Yeah, McLaughlin has no rivals. Back in the 70s he could have assembled one hundred somewhat different Mahavishnu Orchestras and they all would've been excellent or great.
But frankly, to be very impolite, what he has been playing for so many years, with rare exceptions with Shakti, makes no sense and sounds like a screaming of a lonely soul lost in the increasingly incomprehensible wilderness. Even the tone of his supercustom guitars is wrong, I can hear it thru youtube. Not to mention that his bandmates can't play a single note the way it is supposed to be played. Terrible, just terrible. I think, John needs some electroshock therapy. After that either he will start playing what I believe he is still capable of playing or will be gone as a musician altogether. For me either would do but former would definitely be preferred.

Try Steven Wilson. His latest album Hand.Cannot.Erase might be something that you'll like. His albums Grace for Drowning and Raven that refused to sing are also superb. Check out the song Drive Home on Raven. Wait for the guitar solo. If your system can produce deep base all of Wilson's albums have it.

The shorter, tightly composed pieces by the M.O. were often quite good, but the long wailing solos and jams were often boring and indulgent to my ear. I found early Al DiMeola to be more focused and tasteful.

It was the age of the rock n roll dinosaurs, and M.O. should take their share of the blame. On the other hand, we can thank fusion and the like for some of the fine musical genres that were born as a reaction to it.