I recently read "Fighter Pilot" by Paul Richey, who describes his experience in a Hurricane in France in 1939, and have also read "The Mouchotte Diaries" by René Mouchotte, a French fighter instructor who joined the RAF after the fall of France and flew with 615 Squadron.
(The books really complement each other - it's pure coincidence I read them sequentially, but Mouchotte really picks up where Richey leaves, and provides a French perspective on some points observed by Richey from through British eyes. It's also interesting to see the contrast between Richey's somewhat distanced style and Mouchotte's emotional and almost forceful writing. Mouchotte sometimes reminds me of Antoine de Saint-Exupéry - whom Richey had coincidentally met in Paris.)
The interesting thing to observe is that the Hurricane I, equipped with wooden propeller blades and (probably - hard to tell from Richey's account) variable-pitch propellers, gave a good account of themselves in the hands of 1 Squadron - which admittedly seems to have been very well lead. Apparently, 1 Squadron upgraded the Hurricanes in the field with seat armour taken from wrecked battles, elimininating the Achilles heel of the early Hurricanes. Additionally, the squadron leader seems to have ordered a 250 yards single-point harmonization even before commencing combat, figuring that the "Dowding spread" was designed to defeat bombers while they were likely to encounter enemy fighters over France. Another innovation was that the squadron flew with two weavers ("arse-end charlies") instead of the usual single one, making them less vulnerable to surprise attacks.
Apparently, the main fighter opponents of 1 Squadron were Messerschmitt Bf 110 destroyers, against which the RAF pilots apparently achieved a good score, though that's probably more the impression they had at the time - no idea how the actual Luftwaffe losses compare to the British claims. The Hurricane pilots felt they were unable to outrun to the Bf 110, but of course they had no problems out-manoeuvring them. The combat record of 1 squadron is impressive, but Richey (understandably) mentions only the number of pilots they lost, not the number of aircraft destroyed by the enemy, so the picture is somewhat asymmetric. Richey himself was shot down twice, and his books recounts several occassions where other pilots had to bail out, too, but usually they landed in friendly France and were back in action rather quickly. (They might owe this kind of success to their adaption of pilot armour, I figure.)
Osprey's "Bf 109 D/E Aces of the Blitzkrieg" mentions that Mölders and Hahn of JG 53 attacked 3 Hurricanes of 73 Squadron (which did not have the armour 1 Squadron had), shooting down 2 of them - apparently, both were killed instantly in the surprise attack due to the lack of pilot armour. On April 2, Mölders shot down 1 Squadron's "*****" Palmer, an incident also mentioned in Richey's book. Palmer bailed out and survived. (It was his second bail-out in this campaign.)
While Richey didn't fly this particular mission, he certainly took notes very carefully in general, questioning the other pilots to fill his gaps, and no mention of any Me 109 opposition is made - 1 Squadron seems to have been talking only about Me 110s.
With regard to armour and firepower, 1 Squadron pilot Soper came back from the same mission with a severely damaged Hurricane that had to be written off. It had taken 3 cannon shells and 30 machine gun bullets, and he was considered lucky to have made it back due to damage to all controls. His armour plate had "plenty of dents" and probably saved his life.
As far as fighter-vs.-fighter performance was concerned, it seems that the Bf 109D was inferior to the Hawk 75 at least, as the Osprey book mentions that an engagement between 27 Doras of JGr 102 and 9 Hawks guarding a Potez 63 reconnaissance aircraft lead to a score of 4 Me 109s shot down and another 5 crashlanded against just 1 Hawk shot down. (It appears that the Messerschmitts tried to bounce the Hawks, so it's not like they were caught unaware.)
Mouchotte was flying the Hurricane I in combat from October 11, 1940, and his experience was that the Luftwaffe fighters always had the altitude advantage over them, with their Hurricanes invariably forced into a defensive role due to a distinct lack of high-altitude power. More than once, they encountered higher Spitfires, usually helping them but in one case mistaking them for Luftwaffe aircraft and attacking them (apparently realizing their mistake after the formation had broken up, but before actually opening fire). 615 Squadron in that period appears to have had considerable losses and very few successes.
After receiving Hurricane II aircraft, the altitude limit seems to have been pilot endurance instead of engine power, and Mouchotte was very impressed by the type. (In fact, he had been impressed by the Hurricane I, too, considering it a high-performance machine compared to the MS 406 he knew. Richey describes a friendly fire accident between his lone Hurricane and a squadron of MS 406 fighters, by the way - he considered them more manoeuvrable and so relied on his superior speed to escape.)
Mouchotte apparently was quite a capable leader, who was given responsibilities of increasing weight during the war, including command of a British squadron (of which he was especially proud) as well as of Free French units. He was KIA while leading "Alsace" squadron, after being separated from his wingman who, despite being fairly green, showed great promise according in Mouchotte's opinion as recorded in his diary entries. Mouchotte undoubtly was right - this wingman was Pierre Clostermann!
Interestingly, the French translator of 1 Squadron is also mentioned in a book by Bobby Oxpring. Apparently, Moses Damozay - whose subsequent RAF carreer was mentioned in Richey's book, too - flew under the false name of Jean Morlaix (though Oxpring and Richey disagree on what was his real name and what his false name), lone-wolfing it in a personal vendetta against the Luftwaffe. I was surprised to read he survived the war, but it seems he was killed it a flying accident just after the VE day.
Bobby Oxspring, by the way, was the first RAF pilot to report the "channel dash" by the Scharnhorst and Gneisenau battleships. His radio message was intercepted by the Luftwaffe who knew they were discovered, but it still took over an hour before Oxspring's message was believed. Oxspring had been over the battleships simultaneously with Victor Beamish (a station commander at the time) and Finlay Boyd (I never heard of him before, but he was wing commander), and Oxspring comments that though these two, keeping radio silence, had only reported after landing, their combined rank probably lend more credibility to their report than his (as a squadron leader's) had had.