Well the A-5 seems to have a sight at the top and has a front handle but it's $250. The Tippman 98 Custom doesn't have the sight or handle and is $200.
The 98c has a sight, I know mine does at least, it also has a foregrip if thats what you're talking about.. Be sure you're looking at a 98 Custom and not the regular 98.
Tippmans are decent guns what they do best is last a long time and are in good condition, my first gun was a Tippman 98, not custom but the first one lol, I have other guns now but it stills works like it did when I first got it.
Tippmans are the AK-47 of the paintball world. No need to maintain them whatsoever. Personally i own a spyder and an Armotech and love them both. I have used Tippman A5's and customs, i wasnt blown away by them but they were decent. Tons of available parts and upgrades at good prices can make them some damn fine markers.