If I had to choose between the same price, same data amount, 3g speeds or LTE speeds I would choose the 3g (LTE Lite).
Browsing is the same speed, video streaming is just as fast (though lower quality, which is not always easy to distinguish on a small screen).
If you switch from 4GB LTE to 4GB 3G (LTE lite) you will automatically use less data, since your phone uses more data when it has access to higher speeds. You can probably go from 6GB/month LTE to 4GB/month 3G and use your phone the same way you did before. It will use lower quality streams and consume less data by default.
The data caps in Canada are outrageously expensive, so I would ask your provider if you can get your speed lowered if possible to offset this. High speed burning through your data cap within days or a week is not helpful.
They keep bragging about their speeds while increasing the prices for data, I prefer to have lower speeds and larger data caps. I did go from full LTE to LTE Lite (3g) and very much prefer the throttled data, I can use my phone much more with less worry about hitting the data cap.
