Any Garmin GPS's with LM in the name (like 1490LMT) include lifetime maps. I think it's about $30-$50 more. There's other ways *ahem* to get Garmin's current maps if you really want them.
In any case, the must have features I've found in GPS's are:
*Text to speech. Reading out street names is much better than telling someone to turn in 100m. Almost all current GPS's have this feature.
*Lane assist. Knowing which lane to get in for your exit helps a LOT. Especially on the US freeways that have multiple exits.
*Traffic alerts/rerouting. Not always 100% accurate I've found, but better than nothing. Having it auto re-route you is even better as it's one less keypress.
Of the two you listed (the 1350 and the 1490T), here's the
side by side comparison. The main differences is:
*screen size
*junction view on lane assist (shows a picture of the exit graphically so you know which lane to be in rather than just an arrow showing you which lane to go in)
*autosort multiple destinations
*bluetooth
*FM traffic receiver included in the 1490T
Whether it's worth the extra $50 is up to you. I probably would just for the traffic receiver, autosort and junction view. The 1390T is a smaller version of the 1490T if you don't really care about the screen size. You can probably save a bit of money with a smaller screen. Alternately, you might be able to find them for sale on Craigslist (if you don't mind used) as those models are about a year or two old.