New 4Runner is a bit larger and lighter. GX has a V8, but heavier. I think 4Runner will be cheaper in a long run.

You will be happier with the 4Runner in the long run but if luxury and status are things you value then the Lexus might be a more suitable choice. Both should be bought used to avoid some serious first buyer depreciation!

Tough choice, if you can afford the repairs and don't mind spending alot more for smaller things go with the Lexus. 

Both are made by Toyota of Japan. So expect outstanding quality from both. However, I’d give the nod to the 4Runner. The 4Runner is cheaper in price. And the Limited edition is pretty luxurious. You’ll get some nice bells and whistles. 4Runner ride quality has improved greatly over the years as well. 

It depends on if you want the luxury version and care about fancy features and a fancy look, or just want the cheapest vehicle. I myself would choose the 4Runner because it has a more simple v6 engine because the v8s in Lexus's require more maintenance and the 4Runner is cheaper.

4runner. Cheaper to maintain and would last as long as the lexus.

Here's my two cents. Wether you find a used Lexus or Toyota 4Runner, be on the lookout for one with a great CarFax history. Also look for one that's has passed the 120K mile service level. You want the previous owner to plunk down the $$$ for all the "first round" of service intervals up to 120K. That way, you will have weeded out all other owners who are not as diligent in servicing their Lexus and the ones who are less careful about the way they drive them. If no CarFax or service history, check out Scotty's library of videos showing you what to look for in a used vehicle. Remember one thing: BE SCRUTINIZING on the vehicles you check out and don't be swayed by pushy sellers.

If you are looking for a Mall Crawler, not-so-much off-roader, the RX 330/350/400H/450H might be up your alley to look at. If you are planning to Overland or Off-road the Lexus, the GX 470/460 may be the Lexus for you. If you want a heftier trail-capable Lexus, the GX/LX 570. The 470/460/570s are actually Luxury versions of the Toyota's Land Cruisers. They have stout suspensions with an AHC air-lift system and front/rear stabilizer bar control system (KDSS) which is a very expensive option on the Toyota line of SUVs, outside of buying a Land Cruiser. There are 4 wheel-drive models in the RX line, but are not considered off-road vehicles. The ones that are 4WD can tackle snow and are great in bad weather, at the very least (IMHO). The The GX/LX 470/460/570s are 8 cylinder full-time all-wheel drive vehicles. The 470/460/570 denoted engine displacement. The difference between the GX and LX lines strictly denotes the amount of luxury amenities included in the vehicle. 

Good Luck and Happy Trails!