Is it possible to view Saturn in little yellowish and Mars in little
reddish using following telescopes?
It is definitely possible to observe the rings of Saturn with telescopes this size. Even the Cassini division should sometimes appear visible, if the instruments are well collimated and seeing is not too bad. In terms of color, Saturn is just a boring buttery-yellow even in bigger scopes, so I wouldn't worry about that.
But Saturn is getting lower in the sky these days. If you hurry up and get the scope quickly, you may catch it for a few weeks at sunset, low in the western sky. After this, you'll have to wait until next year.
Mars is a different animal. Most of the time, all you'll see is a bright brick-red round dot, even in a bigger scope than these ones. But every couple years Mars is at opposition, when it's closest to Earth. We just had one a few months ago. Then you can see some of the big features, such as Syrtis Major, or the polar ice caps, or Hellas Basin full of frost or fog, like a big, bright white area.
However, that's only doable briefly around oppositions. The scope must be in perfect collimation, and seeing must cooperate.
http://en.wikipedia.org/wiki/Astronomical_seeing
If everything is at maximum parameters, I'm sure you could see Syrtis Major in a scope this size. During the last opposition, I've seen all of the above features, plus more (Utopia Planitia, Sinus Sabaeus, etc), in as low as 150 mm of aperture, in a scope with great optics, perfectly collimated, during nights with excellent seeing.
Anyway, for Mars you'll have to wait until the next opposition, in May 2016.
Later this year, in December, Jupiter will start rising in the East, and you could use your scope to watch it - an aperture like this is enough to see the 4 big moons and at least 2 equatorial belts. It will be high in the sky at a comfortable time in the evening early next year.
Until then, you can always observe the Moon, two weeks out of every four.
Also, the planets and the Moon are not the only things accessible with this aperture. Most of the Messier objects are visible in a 100 ... 150 mm scope, even in suburban areas. M13 is spectacular at any aperture above 100 mm. The Great Orion Nebula is awesome even with binoculars. The Pleiades are great too. Most of these deep space objects require low magnification for the best view, but every case is a bit different.
Plenty of double stars out there, too: Mizar, Albireo, even Polaris. All visible in small apertures.
I am going to buy one of them. Which one is worth more for the money
with the price difference?
The instruments are about the same. In theory, the bigger one has a bit more resolving power and a bit larger collecting area, so theoretically it should be slightly better.
In practice, with mass-produced instruments like these, it usually depends on the build quality, which can vary.
The smaller instrument is an f/8. The longer focal ratio means less aberrations; it also makes it easier for cheap eyepieces to function well, whereas at f/6 ... f/5 a cheap eyepiece may start to exhibit aberrations of its own (independent of telescope aberrations).
Also, an f/8 is easier to collimate than an f/6.
Overall, I would look at it as a matter of price. If you can easily afford the bigger one, get it. Otherwise, the smaller instrument might be a bit easier to maintain, is less demanding in terms of optics, and it should perform pretty close to the other one - all else being equal.
But since you're focused on planetary observations, remember this:
It is far more important to learn to correctly collimate your telescope, and develop it into a routine whereby you do a quick collimation check every time before you observe - it only takes a couple minutes. For planetary observations, the smaller telescope, in perfect collimation, will perform far better than the larger one, uncollimated. Heck, the little scope, perfectly collimated, will perform better on planets than a MUCH larger telescope, uncollimated - that's how important collimation is.
Improper collimation, or lack thereof, is one of the major factors for lackluster performance for a majority of amateur telescopes (along with poor quality optics - but there's nothing you can do about that, whereas collimation can be improved).
Search this forum, or just google, the term collimation, and read the numerous documents you'll find. Or start here:
http://www.cloudynights.com/documents/primer.pdf
Or here:
How can I collimate a dobsonian telescope with a laser collimator?
The owner's manual should also provide some recommendations regarding collimation (I hope).
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