The key these days is "dedicated resources" and then
secondarily how much CPU and importantly RAM, which
is also "dedicated" to your computing processes.
Running a few MT4 instances is not a big load, but I was
running nearly 30 of them, plus a multi-threaded Java
control process over NJ4X.com's API... so.... Ultimately
the VPS provider messed up by failing to execute some
of my threads !!! When I pointed that out, they kinda laughed...
Immediately, I got a dedicated machine and, Big Surprise,
it was the VPS thread mapping which was at its limit !!!
Problem is, you can get a 3 Xeon CPU / 6 gb RAM VPS
setup for $30 / month. But a dedicated machine will cost
you upwards of $90 / month, albeit with 8 processor threads
and maybe 16gb RAM but it's a significant increase for
a dedicated bare metal machine, if you're not really gonna
need that Horsepower and Torque ! LOL
[EDIT] The guys at SeedVPS.com provide real value for
money, but they are into "commodity" computing and are
not gonna offer you much, if any, support... So you need
to find an "I.T. guy" who can help; learn it yourself, or move
up to a more "full service" provider; but, then, you're into
some serious cash outlays...