There haven't been any issues with the server, if people were lagging since the upgrade it was their own connection.
But we can't really tell if this is good enough until we played on it longer, the previous one did fine for a long time until just all at once everything went to shit.
So far so good though.
EDIT: actually noticed several lag *spikes* today, most noticable with redstone, not really a big deal in general apart from that though.
Just the occasional odd piston behaviour breaking a contraption with more advanced redstone.