I have used TOS for the web but only in a minimal fashion. I know what you say when you speak of PC ToS slowing down. You might try upping the ram that the platform will use to increase speed somewhat but other factors (beyond your control) may play a roll here. One factor is your connection speed and how data is routed to your screen. Too many hops through congested routers and your apparent bandwidth starts to shrink. Also how many studies/indicators/charts do you have up and running together? These also place a burden on the platform to keep up with multiple (sometimes complicated) calculations in real time.

But back to your initial question. The web version (IMO) is ok for viewing the market and perhaps making a trade when you are away from your desktop computer. Again this my opinion and I freely admit that I have not given the application a thorough exploration of all its capabilities. I rely on it occasionally when traveling and using hotel Wi-Fi. But to be honest I use the ToS phone app as much or more. Once you get used to the interface it is quite handy as well as very portable.

Hope this helps a little. If you have questions on how to adjust the RAM the the PC ToS uses just post a follow up question. Either I or another member of this forum will probably be able to help you out with instructions.