The EJ-series engine is, for the most part, dead-flat reliable. The EJ22E and EJ22T are both bulletproof. The first-generation EJ25 has a tendency to pop head gaskets and sometimes warp heads due to a design flaw but the second-phase EJ25 seems to be considerably better.
I bought my 1990 Legacy L AWD with an EJ22E and 4EAT automatic tranny about 1.5 years ago and have put on about 43,000 miles since then. The only problem I've had in that time period was a blown head gasket and shot suspension. The head gasket may have been due, in part, to my going close to 20,000 miles without an oil change. The suspension comes with age.
I rebuilt the entire top end of the motor, short of putting in new valves and valve adjusters, re-ran the PCV system with all brass fittings, threw new Magnecor spark plug wires on, fixed the body, added new struts, and I can still tear up the roads as quick as some performance cars.
I love my Subaru...it's so damn easy to work on and has never left me stranded (except when I blew a head gasket and was too scared to try to limp home).