Thinking about how nice it would be to use my Kontakt instruments and other high quality samples in a live performance, so a laptop would be a nice addition to my performance rig. Currently I use my iPad pro, Cubasis, and iReal Pro to playback, and I ahve a lot of Virtual instruments, but the samples are not nearly as good as what I could use via a computer.
I'm wondering what others have done for this purpose--did you get something off the shelf or a custom, professional audio workstation (My studio has a PC Audio Labs custom built computer, and many others (Jim Roseberry, ADK, make wonderful machines). My thinking is custom config might be overkill for what I'm doing live, but then again, who knows, you don't want glitches while performing. I use a PC for my studio, as I mentioned, but also own a Mac Mini, but would love to have Sonar on my laptop, thus I think a PC makes sense in many ways. But VST's could be installed on either platform, and there are MAC compatible sequencers I could surely learn and use if needed-- since I am not really composing on this, just using playback. What makes sense to folks?  I didn't mention my budget, but certainly want to be reasonable (your interpretations are fine, I am flexible). I am willing to spend a bit to get something that works well, but don't want to buy more than I need. Thanks.

How can I move this post to the Computers section? 

I don't do MIDI but I recently bought a laptop for on-site recordings.  It is a Dell Inspiron 15, 5577 model, which is sold as a "gaming" laptop.  It has a 7th generation i5 CPU, 8GB of RAM (upgradeable) and a 256GB M.2 SSD.  Visually the laptop boots and loads (and runs) programs as fast as my DAW desktop that has an i7 6700K CPU. 
 
I had to do some "customizing" and the "picky" Resplendence Latency Mon reports no problems. 
 
The 5577 has space for a laptop hard drive or full size SSD for expansion.  I recently did an on-site recording with it (3 hour show) and used a USB attached hard drive to save the Sonar projects.

There are many options. If you already decided on a laptop, a well spec'd machine should do the trick.I would have two drives. One for OS and one for samples. 
 
 

I like the idea of a custom, audio only machine, it has served me well for my studio/desktop machine for the past 5 years. So many Windows machines seem to have bloatware and settings that then have to be changed to reduce system overload, etc. I may just look into a base-level Macbook, anyway, put my VST's on them, and if I need a sequencer use a mac-compatible DAW (Logic, Cubase, Reaper?), in a scaled down version, for just when I need it.

Why would anyone want to pay 3 to 4 times as much as a Windows PC?  I can configure a Windows PC and save the 3 to 4 times price.

Tru enuf that the MAC is costly without the flexibility to upgrade. Custom PC latptops have multiple hard drives built in, with the Macbook it is likely I'd have to get a very large SSD on it and partition it--not ideal. Not that this is an imminent purchase, but I did see some nice custom builds and they weren't bank-breakers, either.

I have never had any trouble removing bloatware on the computers I didn't build. Most usually include some form of virus software that isn't a full version. Not difficult to remove that. Windows REALLY wants you to use explorer. Not a deal breaker either way there.
What are you planning to do on stage? Play large multi synth sounds?, or really nice bread and butter sounds like pianos and organs? The horns and saxes in Komplete are hard to beat. Nice basses too. This is the kind of thing I'm picturing a cover band would need. You can get close with a nice Yamaha or Korg board too for those kinds of things. I hear ya though. Large sample players are tough to beat.
 
OTOH a keyboardist playing a solo act might want to be the whole band. Then the question is pre made tracks or on the fly? Do you want samples triggered or simple loops on the fly..more like a DJ? You can still do that with a nice sequencer in a mid level keyboard.
 
Several ways to get to the same place.

OP , since you already have a Mac Mini you may want to put MainStage on it first and give that a go just to get a feel .
MainStage comes with every synth , plug and instrument that comes included with Logic .
MainStage only costs around 30 dollars and it is geared totally for live performances ...
If you add what you already have in 3 rd party plugs and synths to MainStage you may find this type of set up to be  pretty versatile ...I have
Full disclosure , I have an i Mac , but more importantly I have a older MacBook that I literally picked up for very low money ...the parent of a college student bought a new MacBook and wanted to get something back to cut the edge of the new purchase price of the students lap top upgrade ..
I use my MacBook w  MainStage all the time as a front end and as hardware into SONAR and my other PC DAW's all the time ...
Imagine what it would be like to get every plug and every synth that comes with SPlat but on the Mac / Logic side of the food chain and only getting it for 30 bucks , then you will know what I'm talking about ..
 
all the best,
 
Kenny
   

I used a generic off-the-shelf i7 laptop with 8 GB of RAM. It's just what I already had, and it started out as just an experiment. I didn't know if I'd need an external interface or if the integrated audio would be OK. Turned out, everything worked fine. Just make sure you turn the wi-fi off. And don't cut corners by falling for a Sunday-paper special with 4 GB of RAM and an i3. 
 
Kontakt worked just fine, as did Omnisphere, Keyscape and of course the lightweight VB3. Unfortunately, I had to stop taking the laptop to gigs because it added to my already-long setup/teardown time and also added to the amount of floor space I take up on stage. Plus I play in a classic rock band where I really only need organ, piano and lead synths.
 
And anyway, the subtleties of deeply-sampled string libraries would be lost on the beer-swilling crowds I entertain. But when and if I ever go back to the low-volume wine-and-cheese crowd, that laptop's definitely coming along.