For more than a decade now, NATS ATCOs haven't done the Approach Procedural course. Instead (as I understand it), they are trained to maintain/achieve separation in the event of a radar failure, but not to provide an on-going approach service procedurally, and the airport ceases IFR movements in the event of radar failure. In the case of the busier airports, this is mitigated by having several radar sources and standby radar displays available. Some non-NATS radar units are also going down that road, although non-NATS ATCOs still generally have the procedural ticket in addition to radar. This means that some airports are able to continue operating procedurally, for instance at night in the event of staff shortage.
As for which is more difficult, it's probably a personal thing. However, if an aerodrome becomes busy enough with IFR traffic that procedural control is causing delays then it will generally install radar. Therefore the procedural units tend to be the ones that have fewer IFR movements - although there are busy procedural airfields and 'one-an-hour' radar units that are exceptions to this.