What's the best laser option for treating clients with slight loss of laxity?

Try non ablative fractional lasers..

Last year, I had a Cutera Pearl fractional treatment on parts of my face. I noticed I had a very good result around mouth and labial folds for tightening, but not as good result around the eyes. Down time was only a few days but I work in the business and am not bothered too much by the look of post treatment erythema.

The skin rejuvenation treatment with a YAG or an IPL can be helpful but the fractional CO2 with a pixel handpiece gets more long term results. Just depends on how much money the patient wants to spend, how long the treatment results lasts and how much down time they will tolerate. I've had numerous treatments myself and there is a difference in what I will do as a touch-up or maintenance months and what needs to be done every 2-3 years.

I would recommend fractional CO2 for the laxity treatment (stronger and deeper treatment, aiming collagen). It is important to choose the manufacturer of the lasers, because low priced models usually don't give uniform treatment which consequently leads to inconsistent results.

I've also used CO2 for several times for reconstructive and cosmetic reasons. IPLs and the YAG are nice for maintenance or upkeep.

You can achieve similar skin tightening using Sciton erbium utilizing both ablation and coagulation settings. What causes the tightening is the heat generated. Pure erbium generates no heat, but if you change the delivery in the coag mode you get heat and hence tightening. The beauty of 'the mix' is you are in total control. Lastly, with the same platform you can switch to deep Profractional treatment with a 5.5%, 11% or 22% total coverage being able to set the depth(up to 1500 microns), energy and coag levels for even more skin tightening. Heat is no problem in types I-III skin types but can start impacting post pigmention (both hyper and hypo) issues in darker skin types.

Anyone ever tried tightening with an ND Yag???
Yes....works great Aerolase's Light Pod Neo

I am not familiar with the "Profractional treatment." Could someone tell me a little about it?

Profractional is the name Sciton gives to its version of Fraxel. I used Fraxel for years and found there were limits to its technology. Specifically no tightening although it did wonders for texture, porosity and superficial acne scarring. It also had disposable tips which added to consumable costs. Profractional uses erbium as well and can be set to a percentage of coverage done in one pass, not 8 or more like in Fraxel. It can be set to up to 1500 microns of depth(not sure where Fraxel is at this point in time but I think their max is around 200 microns) and you can actually throw in some heat for tightening in specific areas. Erbium energy if delivered in stacked pulses will heat tissue just like CO2, but in a more controlled manner. Also, zero consumables with Profractional. Hope that helps with the comparisons.