I was wondering if an Ultra Stick 40 would make a good 2nd plane?
and do'se it have any bad habbits.

I think it depends on your skill level with the trainer. Talk to your instructor.

I have an US40 and a Tiger 2 ARF. When I was learning, the Tiger 2 was easier to fly, a little more stable and I wasn't trying to play with all of the options on my radio with it. The US40 flies slow and steady or fast and furious depending upon the setup. I've set mine up with an OS 46FX and a 11.5 prop and it will climb almost forever. It's very acrobatic and I love playing with the flaps and experimenting with the crow. I can land it as easily as the Tiger 2 w/o flaps. When I was learning to fly it, I would stand behind it to get the feel of a taildragger but that's easily learned after a few times.

Look of the modifications here in the forum regarding the landing gear and firewall.

Good luck

An Ultra Stick 40 is a great 2nd plane as long as you can land and take off without much effort with your trainer. Have someone at your field to show you the proper way to land and take off with a taildragger. I have a Hanger 9 Super Stick 40 and a Hanger 9 Ultra stick 60.

A good second plane also is a Sig Four Star (40 or 60 size). I have the 60 size which is a very good low wing taildragger plane.

DTB

My Ultra Stick 40 was my second plane. I've had it for 2 years and I still love taking it out to the field. Very easy to fly and land. Build it with the quad flaps. It will definitely keep you entertained.

I built mine with the intentions of adding floats, but the total flying weight of 6.5 lbs scared me away from adding almost another pound of float gear. I used a Saito .82 and was surprised to need about 3 oz of tail weight. Nevertheless, it flies great and I use it in our club fun flys. I put quad flaps on mine as per instructions, but believe it performs a "dive landing" much better if the radio is programmed to raise the flaps and ailerons, versus splitting them. I tested the plane both ways and it definitely slows down better if all surfaces are raised. Yes, I suggest the US 40 would be a good second plane, particularly if an experienced RC pilot sets it up for you to fly more docile. When you are ready, it can be made to dance. Definitely add support to the landing gear block, be cautious of the wing dowels (they may wear significantly), and I would consider using Du-Bro landing gear. BTW; the Saito .82 with APC 14 x 4w pulls 9.4 lbs. Since the plane weighs 6.5 lbs it has great vertical. It will soon do better because I will rearrange the radio to eliminate the tail weight; along with smaller battery and throttle servo. Good luck.