The motor is a basic iron-block Over-head Cam V8 with coil-on-plug setup. No other frills except later models which have a secondary air pump (which they place in the vee) and also the starter (which is in the vee). The SAI was added to later models with the Variable Valve Timing (so yeah, later models have VVT which makes the cam-seals a bit more difficult to swap. Timing belt job itself remains the same.

Which means maintaining those parts isn't exactly hard, but can be costly (if you have a shop do it) because of the work required to get "in there".

It also has a propensity to crack the exhaust manifold, giving you a notable tick at warm-up until the metal expands and it seals itself. Many ignore it.

My '08 has the tick. My '03 does not.

In short, it's a tad more complex than a good 'ol push-rod V8, but not by much. It's as simple of a OHC V8 as you can get. I've had two M62 V8s which are dream when they run, but they always scared me by about 150k miles (particularly the special tools required to service it). I have no such fears with the Toyota V8.