I stayed at the Marriott Portsmouth on Saturday night last (4th February) as was attending a mini-party.
On check-in the lady at Reception was courteous, professional and welcoming. The room was clean, spacious and bathroom a generous size.
The ice machine on the 2nd floor did not work but a lovely employee on passing and seeing me struggle, insisted on getting me some from downstairs - she gets 110% on customer fulfilment.
The pool area is very small and is cumbersome to swim in when the attendance level increases.

I had booked a meal for 10 of us in the restaurant area and had mentioned prior that it was a 'special occasion' to which I was told they would assure the night was marked in some way by the hotel.

They also had an Hairdressing Awards do there on Saturday night which tended to monopolise the bar area early evening (couldn't be helped). The bar staff were very slow and the bar drinks are limited in certain areas, not the prices I may add.

The restaurant 'Sealevel' is by reception and inside the main entrance door which leaves nothing to intimacy, ambience or style. Before the party arrived I had to speak to the 'manager' about securing 2 credit cards to pay for the meal as they said it was not policy to pre-take a credit card. I understand this from the perspective of security but I did explain that I wanted some arrangement made rather than a 'haggle' for the bill at the end of the night and after affirming myself and the fact Marriott are a global hotel that should be more flexible a compromise was made!

I had booked our table for 8:30pm and by 9pm they were still not ready to seat us - which in fairness did not pose too much of an inconvenience.
Of course when we were seated there was absolutely nothing to indicate our 'special' get together or otherwise despite the lipservice from the man who took my booking several days earlier. Anyway, on ordering our starters we were then told that '3' were not available(!) much to the disgruntlement of many in the party. We then ordered alternatives and I had to demand complimentary bread due to the inconvenience of a late seating and 40% of the starters not available.
Our meal was good all round and the service was good.
Breakfast the next day was better than average but does not warrant a price tag of £15+ (my booking included it).

On checking out we were unfortunate to be greeted by a stone-faced, brusque receptionist who lacked much. When I enquired about the Marriott Rewards, she responded to the question but did little to ensure I had understood or elaborate.

So all in all, not what I expected from this hotel brand.

Not highly impressed by Marriott's Spa facilities, if anything a little bit dated, but with very helpfull, smiley staff.
Also would recommend massage and facial, as was very relaxing in lovely surrounding.
Can't comment on hotel/rooms, as didn't stay overnight, but would happily come back for beauty treatment.

Stayed in January for one night. Bedroom was good and what you would expect from Marriott. Avoid the bar as slow and poor service. Nice atmosphere in hotel lobby. Impressed when I checked out and left the hotel I revived a call about something I had left in the room which could have just gone to lost property.

Just stayed at this hotel for the weekend and the hotel itself is excellent, the only slight downside is its a little "out of town". Nice pool etc. free parking helps too.