I'll go with the first. More watts (heats faster, holds heat a bit better), less things to fail.
The first model is similar to something Radioshack (if i remember correctly) sold in US. You just squeeze ball, put iron over the spot, release the ball and it will suck solder. Downside: until you get used with it, you need both hands.
The second one is only 30 watts so it will take more time to heat up between suctions. It will be LARGE and hard to hold in hand (it will be hard to keep in hand as you normally hold a solder iron or a pen) . While you can use one hand to desolder (and press that tiny button) your hand will get tired from holding it. Also, the pump will vibrate and move the pump so if you try to clean some surface mount solder, it's hard to use. You basically have to have a lead stuck in the tip to keep the gun in place when doing suction.
The gun will also require you to replace filters on it, which are there to prevent solder from getting in the pump.. and the pump won't suck well if the filters are clogged...