Hi,
Beside LCD screen, that you need to pay apart heavily, I still couldn't find advantages of buying a T490(s) against E490 that justify the double of the price of former. By the contrary, you get following drawbacks when buying:
a) T490:
. Impossible to update wifi card, as it is integrated at motherboard;
. Impossible to choose discrete graphics card, unless you choose i7-8565U (in Europe, at least);
. 8GB or 16GB memory soldered to systemboard --> only one DDR4 SO-DIMM socket;
. T490s:
. Impossible to update wifi card, as it is integrated at motherboard;
. Impossible to choose discrete graphics card, whatever preocessor;
. 8GB or 16GB memory soldered to systemboard only (not possible to add more RAM later (Lenovo system configurator only shows these two possibilities, PSREF shows a third one);
Considering above, T490 and T490s are models designed for those that in max 5 years replace their portable computers.