personally, leaks were my biggest problem starting out. welp, i have both 1.4 and 1.5. i typically use 1.4 for somethings, and 1.5 makes a few things less complicated.
if leaks are a consistant problem, then id seriously suggest using 1.4. 1.5 has a feature missing. the find next leak function under the misc menu. its by far the superior of the line as far as funcions it was capable of. they dumbed down 1.5 a touch to make it more stable. i dunno how it did, because my pc likes 1.4 better anyway. that may solve your crashing problems as well. though some programs have issues with using the same file at the same time as another.