I almost bought a Portuguese Chipmunk once on the basis of it being a fun plane and my affinity for 'antiquey' stuff. What turned me off was the engine, and the fact that on this example the owner literally had to mop pools of oil oil out the cowling with rags after every flight. I'd expected something more like a US or Russian radial but the Gipsy design isn't that advanced - its more like a 1920s engine.
Its a roughly similar situation with the local (US) Bücker Jungmanns - we have a great many locally, with the numbers having grown slowly but surely since the 60s. Over the years and with so many Tigre and (to a lesser extent) Walter Minor engine failures, the owners accepted reality. At least in compensation they climb at a tremendous rate now, don't leak and don't need to be treated like museum pieces. The Gipsys are more reliable than a Tigre but no less fiddly and leaky.