[Sven]

From a pilots account:

Me 109 G:
"- What effect does the weapons' recoil have?
Nnooo, it has no effect, you don't push the trigger all the time. You fire accurate shots. And you don't have so many rounds.
- Smoke? The smoke of the cannon or the mg's? Does it affect visibility when firing?
Nothing, no smoke, no effect to view."
- Väinö Pokela, Finnish fighter ace and Me 109 trainer. 5 victories. Source: Interview of Väinö Pokela by Finnish Virtual Pilots Association.

Not a 110 but a 109 with only half the guns in the nose, but as you can read his vision is not troubled at all.

Some more notes:

About gun muzzle flashes on Me 109 G:
"I have specifically asked this from Kyösti Karhila, a FiAF H75A and Bf 109 ace.
Of the shake he noted that there practically was none, and in fact you had hard time even hearing your guns firing because there is so much other noise in a fighter aircraft. This is specially interesting as his preferred ride in Bf 109's was the three cannon Bf 109 G-6/R6. Same with the muzzle flash, he dryly noted that there was none visible to the pilot, not even from the 13mm cowl guns.
For marketability reasons these effects just seem to be generally overmodelled in some flight simulators. Possibly because of the muzzle flashes in Hollywood movies, where blanks are being fired. Blank ammo does cause sizable muzzle flash, because the powder is different from the one used in live ammo, and because there practically is no bullet slowing down the exit of the hot gases."
- Pentti Kurkinen, enthusiast

Me 109 G:
"- The Messerschmitt was equipped with two 13 mm MGs in the nose, were there muzzle flames or anything else visible in the cockpit when shooting?
You see just the tracers if any. No glare, no flames. The rate of fire of the MGs was so high that you cannot see anything. The cannon ammunition comprised five types of shells each smoking in their way. There were high explosive, armour piercing, tracer and some other types."
- Kyösti Karhila, Finnish fighter ace. 32 victories. Source: Interview by Finnish Virtual Pilots Association.

More over at: http://www.virtualpilots.fi/feature/articles/109myths/