I'm new to playing support and i was wondering which would be better (and easier) for a noob..
Lulu's ult is good with bruisers so they can get more health, however sona's ult can stun an entire team
Which is better for a noob

I have played both. I may be biased because Sona was the 1st support I ever played....I'd have to say Sona is much much more fun

Lulu has a much higher skillcap but offers more reward when mastered.

It is always hard to pick up supporting role for the first time. For a total noob who knows really nothing about supporting i suggest Lulu as she is tankier than Sona, has a higher range and if you make a mistake you can use your shield to protect yourself or your adc from being bursted down.

After you became a bit more familiar with supporting role, i suggest picking up Sona. She is one of the strongest supports in the game as of now. She has a great poke, sustain, speed buff, and aoe stun, even bonus damage/armor via her passive. Her only problem is her defensive abilities which is one of the worst if not the worst out of all champions, so if the enemy manages to catch you out of position(and since you are new at supporting they will), you are going to die.

sona is more magelike
lulu is more supportlike

Both are solid.

Lulu is way way more comp reliant. But also way way more powerful with the right comp.

Sona is good too though.

She also offers healing which makes her a sustain lane champion and at lower skill level play her ult can be very devastating.

Sona is more "noob friendly". She can make just as big plays as Lulu with her ult. Lulu offers a bit more poke, and a bit more disruption through her kit, but is harder to play, thus more rewarding.

Look at the team comp

Do you have a bunch of AoE on your team? Do you have little to no intiate? Do you have other Aura based champions? Sona works for comps like this, you can initiate for you team, especially if you have an AoE person, the stun locks them down for that person to own them. Her poke/heal makes the bot lane easily sustainable, and the auras help for overall beefiness.

Do you have other High Risk/High Reward toons on your team? Do you have an initiater who will most likely get focused hard? Do you have a hypercarry? Lulu works best for this, w/ her shield, you can help the initiate, and your ADC lane prevent damage. The speed boost she offers is good for your initiate to get to the center of their team fast, not to mention to you have a HP buff/knockback if used properly, which can save any teammate instantly. Her slow is also good, and your have a stealth reveal w/ pixie if they have an akali,twitch,talon,khazix, vayne.

Make lulu be the adc and sona as support
Bottom lane will be so much fun

i recommend sona, best support in the game, nice heal/amazing poke with added effects (damage decrease (if an assassin leaps in) slow, or a small nuke and an ult that, if landed across 3 or more people, is almost an assured win

that being said lulu sure pokes harder, but i have 0 lulu exp, while sona is the reason im not in 800 elo anymore