shakiroin
You are really cutting across social, cultural, and economic lines with this one. The biggest dichotomy here is one of age. Older musicians, particularly the non-keyboard players of the band have much less trust (faith ?) in computers than younger musicians, while many younger musicians can't even conceive of going to a gig without their laptop, but there are cultural overtones as well. There are a lot of bars and bistros where your laptop will draw sidelong glances, not only from the other band members, but from the clientele as well, but just as many dance clubs where showing up without a laptop will get you thrown out on your ear as being ill-equipped. So when you ask about the reliability of the equipment involved, the answers you get are going to depend mostly on who you ask. I gave up gigging many years ago. What I do here in the studio today, I could not do without my PC, but if I WERE to go out on a gig, I would be hard pressed to consider hauling my laptop along. Oddly enough, I would probably be more likely to set up something on the iPad and take it with.
Now, as for the equipment, and using hardware out of yesteryear - let's look at what is available (new) on the market right now. Roland's entire "New Era" line of sequencerless synths - the Jupiter-50 and its monster brother, the Jupiter-80, and the MOTL Juno-Gi, and even the loveable little cuddly Di - ALL still have 5-pin-DIN MIDI connections. The Jup-80 even still includes a discrete 5-pin-DIN MIDI THRU. Even though Casio would love to have their upgraded 5-pin-DINless CTK/WK-6XXX/7XXX workstation line viewed as entry-level pro, the two they had to absolutely have considered pro-level for survival - the XW-P1 and the XW-G1 - are equipped with 5-pin-DIN MIDI IN/OUT jacks. In a couple of other threads in these forums, you have expressed interest in the Yamaha MOX6. The MOX's, being part of the pro Motif line come equipped with the full house 5-pin-DIN MIDI IN/OUT/THRU. I can not say for Korg, because I have never been a Korg user, but I have to assume that their line follows suit. I am a firm believer that these manufacturers are doing this for one reason, and one reason only - for market perception rather than customer need. They appear to realize that even in this day and age, a drop of the 5-pin-DIN MIDI jacks is a drop from pro level to fringe level, at best, as far as their target market is concerned. Roland appears to be taking an obvious hit just from dropping their sequencers. I never ceased to be amazed at the number of younger musicians on these forums that express no interest in a particular unit because it has "no MIDI', meaning it has USB-MIDI, which they equate to "no MIDI".
So, back to your original question. The core or main equipment you choose will determine your flexibility in choice of peripheral gear, but if you like discrete hardware like sequencers and sound modules, etc I think you will be safe considering those as long as you stay with MOTL keyboards and above. I think the 5-pin-DIN market will still be here for a while. Is it more reliable ? WELL - that still all depends on who you ask ! BTW - Even though I don't gig anymore, there are still a bunch of us that get together from time to time for jam sessions. I don't dare take one of my arrangers, as the guys feel it upstages them, but we do need some help once in a while with some backing tracks, so I haul along some MIDI files to play with the MC50-Mk-II through the Gi. As a matter of fact, I still have a battery powered Yamaha MIDI Data Filer that I use from time to time. All I can say is that none of this equipment has ever "crashed" on me.
