The two types are just variety. Neither is superior to the other. I fly both, and am not about to give up either.
The favorite electric I have is (was, it's met its fate) a Kyosho Cessna Cardinal, with the stock engine and prop. I flew it with either 7 cell 1800 NiCad or 6 cell 3000 NiMH cells. Two of the 7 cell packs date back 10 years when I first got the plane, and the NiMH packs are about 5 years old. The NiCads got about 5.5 to 6.5 minutes, and the NiMH packs get about 12 minutes, although I could fly longer on good thermal days. For longer flights, you just fly the model the way the full size planes are flown; max throttle for takeoffs, go-arounds, and aerobatics, and a lower cruise setting for the rest.
I get relatively good life out of both kinds of battery packs. I just don't pay to much attention to what the competition car drivers say, and pretty much go by what the battery manufacturers say. I never charge a hot battery, I charge at a C3 or lower rate, I never use a discharger between charges (I bought an electric that had an automatic discharger/charger as part of the package. Burnt up a 650 mah NiMH the first time I used it. The second pack started overheating on my second try, so I pitched the device). If a pack has been setting unused for over 5 or 6 months, I'll slow charge it before using it.
Electric park flyers are slower. The third fastest R/C plane I ever flew is a brushed 400 Wattage Mirage 2000 that I've had about 5 or 6 years. It's faster than most of the 40 or 60 powered glow trainers with the Graupner prop I'm using. For comparison, the fastest plane I had was a Quickie 500 with a high end sport 40 BB engine that had a pitch/rpm speed calculation of about 135.
You can also get higher powered electrics that hold their own against the glow planes. An engineer in another department put an Astro Geared 25 on an Ace Sundancer, and has witnesses swear it's faster than some glow 40 powered versions, and easily gets 8 to 10 minute flight, depending on how he controls the throttl. It'll do anything the glow versions do.
If you treat your batteries with respect and care, they'll last a long time, and could end up costing what a glow plane will over the same time, or maybe even slightly less. Abuse the batteries, and the electric will make your wallet wish you had glow over that same period.
Electric Park Flyers, Electric 3D, Glow trainers, Glow sport, Glow or Electric scale, whatever. Try whichever you think you have an interest in and the time and money to get involved with. Concentrate on whichever suites your skills interests and time aand money availability best. Don't dismiss any of the others. In fact, to sample the variety you can have in this hobby/sport, you might even look into the various facets of Control line and Free Flight. They also have the Glow/Electric mix nowadays.
Enjoy life, don't get caught up in making a hobby out of putting things down.