In my book, Peter Davison is second only to David Tennant as the Doctor. This set contains two serials, both of which have their merits.
“Time-Flight” was the first episode after the departure of Adric, a companion of the Doctor. At the time, there were 3 companions, Adric, Tegan and Nyssa, and the departure of one of them was needed – even though this was the last serial in the series. At the end, Tegan is left behind, but comes back in in the other serial in this set, “Arc of Infinity”. (The BBC didn't want to pay her a retainer, so effectively let her go, only to rehire her mid-year the next year.) The only major problem with Doctor Who in the 80's is that the acting has a Shakespearian hangover – with an unhealthy dose of melodrama thrown in. Notwithstanding, Time-Flight is a well written episode, and I enjoyed the unveiling of the real villian.
“Arc of Infinity” was interesting for me, seeing the Time-Lord Society, which, according to the current series, was completely destroyed in the Time War. (Colin Baker's performance, though not yet the Doctor, is interesting, to say the least). I loved the fact that Sarah Sutton as Nyssa got more screen time, she is still one of my favourite companions.
Overall, as far as Doctor Who from this era goes, two of the better serials. Even if the special effects are pitiful by today's standards.