The Romans has a considerable, and surprisingly effective, comedy element, carried almost entirely by Hartnell's Doctor. On a whim, he decides to leave their holiday villa and go to Rome (taking Vicki with him) pretending to be a murdered musician, and succeeds in fending off Nero's jealous attempots to have him killed. There is a much less funny sub-plot involving Ian and Barbara, kidnapped by slavers, who also end up in Rome - Ian as a gladiator, Barbara as palace slave, pursued by the lustful Emperor - before making their escape. (Somewhere there must be a definitive list of the characters who have lusted after Barbara: Ganatus in a very gentlemanly way in The Daleks, the much nastier Vasor in The Keys of Marinus, the equally nasty El Akir in The Crusade, and now Nero.) The Ian/Barbara chemistry is very sweet - they have a nice joke between them about looking in the fridge. The script rather neatly resists bringing the travellers together, so that neither the Doctor and Vicki nor Ian and Barbara ever discovers what the other pair of characters is up to in Rome. Hartnell is simply superb, utterly watchable, imperious, funny, devious. It's a shame that Maureen O'Brien can't quite rise to the challenge of being his straight man, but this was only her second story, so I suppose one must make allowances.
The Space Pirates features the TARDIS crew getting caught up in a conflict between pirates and law enforcement in outer space. My biggest problem with it was the accents of two of the key supporting characters: General Nikolai Hermack, played by plummy-voiced Jack May, later briefly famous as Garkbit the waiter in the Hitch-Hikers Guide to the Galaxy and less briefly as Nelson Gabriel in The Archers, who can't quite decide if he is doing his usual toff or something slightly more foreign; and even worse, Gordon Gostelow's veteran miner Milo Clancey, whose voice wanders all over the southern and western United States with hints of Irish and Antipodean as well. Especially when you have to experience five of the six episodes on audio, and #3 is of particularly bad quality, it is a real distraction from your enjoyment. Having said that, it's not as bad a story as some people say, though it is rather unusual - the Doctor and his friends are more acted upon than acting, and spend a lot of time trapped or locked up while the story continues around them. To judge from the surviving episode, it looked like a half-decent effort, though my long-buried physicist instincts slightly rebelled at the immense violations of celestial mechanics committed by the writer.
Neither of these is essential Who, but both had their good points. The Romans is worth getting for amusement, The Space Pirates only for completists I think.